mmiffw. 


jy*T*T* 


THE  LIBRARY 

OF 

THE  UNIVERSITY 
OF  CALIFORNIA 


PRESENTED  BY 

PROF.  CHARLES  A.  KOFOID  AND 
MRS.  PRUDENCE  W.  KOFOID 


UJJfy 


„ 


LATELY  PUBLISHED  £F 
CAREY,    L.EA    &    BL.ANCHARD, 


PHILADELPHIA. 


A  TREATISE  ON  PULMONARY  CONSUMPTION, 

Comprehending1  an  Inquiry  into  the  Cause,  Nature,  Prevention,  and  Treatment 
of  TUBERCULOUS  and  SCROFULOUS  DISEASES  in  general.  By  JAMIJS 

CLARK,  M.  D.,  F.  R.  S.,  &c.     Ml  vol.  8vo. 
f*       f 

"  Dr.  Clark's  Treatise  on  Consumption  is  the  best  that  1ms  yet  bee«  published  in  this  coun- 
try, or  on  the  continent.  It  shows  an  intimate  knowledge  of  the  approved  methods  of  diag- 
nosis, and  of  the  morbid  anatomy  so  successfully  investigated  by  the  continental  pathologist?, 
and  by  Professor  Carsvvell ;  while  it  displays  an  acquaintance  with  the  resources  of  the  sys- 
lem,  and  the  power  of  the  therapeutic  agents,  only  possessed  in  this  country  and  in  Germa- 
ny."— Lancet,  August,  1835. 

DUNGLISON  ON  HYGIENE. 

On  the  Influence  of  Atmosphere  and  Locality;  Change  of  Air  and  Climate,  Sea- 
sons, Food,  Clothing,  Bathing1,  Exercise,  Sleep,  Corporeal  and  Intellectual 
Pursuits,  &c.  on  Human  Health,  constituting  Elements  of  Hygiene.  By  ROB- 
LET  DUNGLISON,  M.  D.,  Professor  of  Materia  Medica,  Therapeutics,  Hygiene, 
and  Medical  Jurisprudence  in  the  University  of  Maryland,  &c.  In  1  vol.  8vo. 

"The  want  of  a  precise  and  practical  compendium  of  the  principles  of  hygiene,  has  long 
been  felt  in  this  country,  especially  by  the  younger  members  of  the  profession,  who  from  the 
deficiency  of  elementary  treatises,  and  still  more,  of  a  proper  course  of  instruction  on  this  im- 
portant subject,  are  in  a  great  measure  obliged  to  rest  content  with  the  general  views  of  the 
operations  of  external  agents  on  the  human  organization,  which  they  acquire  whilst  pursuing 
the  general  routine  of  their  medical  studies."— American  Medical  Journal  for  February. 

"  We  can  recommend  this  work  to  the  public  with  the  utmost  confidence,  as  one  of  the  best 
treatises  on  the  subject  we  possess." — Ibid. 


DENTAL  SURGERY. 
A  SYSTEM  OF  DENTAL  SURGERY, 

In  three  Parts.  I.  Dental  Surgery  as  a  Science  II.  Operative  Dental  Surgery. 
III.  Pharmacy  connected  with  Dental  Surgery.  By  S.  S.  FITCH,  M.  D.  Se- 
cond edition.  In  1  vol.  8vo.  With  numerous  copperplate  engravings. 

ANIMAL  AND  VEGETABLE  PHYSIOLOGY, 

Considered  with  reference  to  Natural  Theology.  By  PETER  MARK  ROGET,  M.  D. 
Illustrated  with  nearly  500  wood  cuts.  In  2  vols.  8vo.  Being  a  part  of  the 
Bridgewater  Treatises. 

THE  HISTORY,  HABITS,  AND  INSTINCTS  OF  ANIMALS.  By  the  Rev. 
WILLIAM  KIKBT,  M.  A.,  F.  R.  S,  In  1  vol.  8vo.  Illustrated  by  numerous  en- 
gravings on  copper.  Being  a  part  of  the  Bridgewater  Treatises. 

THE  PRACTICE  OF  PHYSIC.  By  W.  P.  DEWEES,  M.  D.,  Adjunct  Professor 
of  Midwifery,  in  the  University  of  Pennsylvania.  New  edition,  greatly  en- 
larged. Complete  in  1  vol.  8vo. 

"  We  have  no  hesitation  in  recommending  it  as  decidedly  one  of  the  best  systems  of  medi- 
cine extant.  The  tenor  of  the  work,  in  general,  reflects  the  highest  honour  on  Dr.  Dewees's 
»alents,  industry,  and  capacity  for  the  execution  of  the  arduous  task  which  he  had  undertaken. 
It  is  one  of  the  most  able  and  satisfactory  works  which  modern  times  have  produced,  and  will 
be  a  standard  authority."— London  Med,  and  Surg.  Journ.  dug.  1830. 


DEWEES   OX   THE    DISEASES   OF   CHILDREN.     Sixth   edition.     In 

1  vol.  8vo. 

The  objects  of  tliis  work  are,  1st,  to  leach  those  who  have  the  charge  of  children,  either  a* 
parent  or  guardian,  the  most  approved  methods  of  securing  and  improving  their  physical  pow- 
ers. This  is  attempted  by  pointing  out  the  duties  which  the  parent  or  the  guardian  owes  for 
this  purpose,  to  this  interesting,  but  helpless  class  of  beings,  and  the  manner  by  which  their 
duties  shall  be  fulfilled.  Arid,  'Jdly,  to  render  available  a  long  experience  to  these  objects  of 
our  affliction  when  they  become  diseased.  In  attempting  this,  the  author  has  avoided  as  much 
as  possible,  "technicality;"  and  has  given,  if  he  does  not  flatter  himself  too  much,  to  each  dis- 
ease of  which  he  treats,  its  appropriate  and  designating  characters,  with  a  fidelity  that  will 
prevent  any  two  being  confounded  together,  with  the  best  mode  of  treating  them,  that  either 
his  own  experience  or  that  of  others  has  suggested. 

DEWEES  ON  THE  DISEASES  OF  FEMALES.    .Fifth  edition,  with  Addi- 
tions.    In  1  vol.  8vo. 


A  COMPENDIOUS  SYSTEM  OF  MIDWIFERY;  chiefly  designed  to  facili- 
tate the  Inquiries  of  those  who  may  be  pursuing  this  Branch  of  Study.  By 
W.  P.  DEWEES,  M.  D.  In  1  vol.  8vo.  with  13  plates.  Seventh  edition,  cor- 
rected and  enlarged. 

A  NEW  EDITION  OF  GIBSON'S  SURGERY. 

THE  INSTITUTES  AND  PRACTICE  OF   SURGERY;  being  the  Outlines 

of  a  Course  of  Lectures.  By  WILLIAM  GIBSON,  M.  D.,  Professor  of  Surgery 
in  the  University  of  Pennsylvania,  &c.  &c.  Fourth  edition,  greatly  enlarged.' 
In  2  vols.  8vo.  With  thirty  plates,  several  of  which  are  coloured. 

"The  author  has  endeavoured  to  make  this  edition  as  complete  as  possible,  by  adapting  it 
to  the  present  condition  of  surgery,  and  to  supply  the  deficiencies  of  former  editions  by  add- 
ing chapters  and  sections  on  subjects  not  hitherto  treated  of.  And,  moreover,  the  arrangement 
of  the  work  has  been  altered  by  transposing  parts  of  the  second  volume  to  the  first,  and  by 
changing  entirely  the  order  of  the  subject  in  the  second  volume.  This  has  been  done  for  the 
purpose  of  making  the  surgical  course  in  the  university  correspond  with  the  anatomical  ler- 
tures,  so  that  the  account  of  surgical  diseases  may  follow  immediately  the  anatomy  of  the 
parts." 


DUNGLISON'S  PHYSIOLOGY. 

HUMAN  PHYSIOLOGY;  illustrated  by  numerous  Engravings.  By  ROBLEY 
Duwoi.is6jf,  M.  1),,  Professor  of  Physiology,  Pathology,  See.  in  the  University 
of  Virginia,  (now  of  the  University  of  Maryland,)  Member  of  the  American 
Philosophical  Society,  &c.  in  2  vols.  8vo. 

"This  work,  although  intended  chiefly  fur  the  professional  reader,  is  adapted  to  the  com 
prehension  of  every  one.  the  anatomical  and  other  descriptions  being  elucidated  by  wood  cuts 
and  by  copperplate  engravings.  It  compos  a  full  investigation  of  every  function  executed 
by  the  various  organs  of  the  body  in  health,  and  is  calculated  to  convey  accurate  impressions 
regarding  all  the  deeply  interesting  and  lnygv,Jrjous  phenomena,  that  are  associated  with  the 
life  of  man— both  as  an  individual,  and  a  spot's—and  a  knowledge  of  which  is  now  regarded 
as  indispensable  to  the  formation  of  a  well  educated  gentleman." 

"  It  is  the  most  complete  and  satisfactory  system  of  Physiology  in  the  English  language  It 
will  add  to  the  already  high  reputation  of  the  author."— American  Journal  of  the  Medical 
Sciences. 

"  A  work,  like  this,  so  abounding  in  important  facts,  so  correct  in  its  principles,  and  so  free 
from  errors  arising  from  a  prejudice  to  favourite  opinions,  will  be  cordially  received  and  ex- 
tensively consulted  by  the  profession,  and  by  all  who  are  desirous  of  a  knowledge  of  the  func- 
tions of  the  human  body,  and  those  who  are  the  best  qualified  to  judge  of  its  merits,  will  pro- 
nounce it  the  best  work  of  the  kind  in  the  English  language."— Silliman. 

"This  is  a  "work  of  no  common  standing;  it  is  characterized  by  much  learning  and  research 
contains  a  vast  amount  of  important  matter,  and  is  written  by  a  man  of  taste.  We  are  in  • 
clined  to  think  that  it  will  be  placed  by  general  consent  at  the  head  of  the  systems  of  Physio- 
logy now  extant  in  the  English  language.  Nor  are  we  prepared  to  say,  that  all  things  consi- 
dered, its  superior  exists  in  any  language.  It  has  a  character  of  i ts  own,  and  is  a  true  Anglo 
American  production,  unsophisticated  by  garnish  foreigniffm."— Transylvania  Jutrnal. 


TREATISE 


ON 


SPECIAL   AND    GENERAL 

ANATOMY. 

BY  WILLIAM  E.  HORXER,  M.  D. 

PROCESSOR  OF  ANATOMY  IN   THE  UNIVERSITY    OF    PENNSYLVANIA— MEMBER  OF    THE    IMPERIAJ 
MEDICO-CHIRUROICAf.  ACADEMY  OF   ST.  PETERSBURG— OF  THK 
AMERICAN  PHILOSOPHICAL  SOCIETY,  &C. 


VTiiltinn  adhuc  restat  operis,  multumque  restabit,  nee  ulli  nato,  post  inille  sa?rula 
praerlmlitur  occasio  aliquid  adjiciendi. 

8ENECA,  EPIST, 


IN  TWO  VOLUMES, 
VOL,.  II. 


FOURTH  EDITION,  REVISED  AND  IMPROVED. 


CAREY,   L.EA  &  BLANCHARD. 

1836. 


JAN  9    '36 


Eastern  District  of  Pennsylvania,  to  wit: 

BE  IT  REMEMBERED,  that,  on  the  seventeenth  day  of  October,  in  the 
fifty-first  year  of  the  Independence  of  the  United  States  of  America,  A.  D. 
1826,  WILLIAM  E.  HOHNER,  of  the  said  district,  hath  deposited  in  this  office  the 
title  of  a  book,  the  right  whereof  he  claims  as  Author,  in  the  words  follow- 
ing, to  wit:-— 

"  A  Treatise  on  Special  and  General  Anatomy.  By  William  E.  Horner,  M.  D., 
Adjunct  Professor  of  Anatomy  in  the  University  of  Pennsylvania — Member  of 
the  American  Philosophical  Society— Surgeon  at  the  Philadelphia  Alms 
House,  &c.  *  Multum  adhuc  restat  operis,  multumque  restabit,  nee  ulli  nato, 
post  mille  szecula  praecluditur  occasio  aliquid  adjiciendi.'  Seneca,  Epist.  In 
Two  volumes.  Vol.  II." 

In  conformity  to  the  Act  of  the  Congress  of  the  United  States,  entitled,  "  An 
Act  for  the  Encouragement  of  Learning,  by  securing  the  Copies  of  Maps, 
Charts,  and  Books,  to  the  Authors  and  Proprietors  of  such  Copies,  during  the 
times  therein  mentioned" — And  also  to  the  Act,  entitled,  "An  Act  supplemen- 
tary to  an  Act,  entitled,  'An  Act  for  the  Encouragement  of  Learning,  by  se- 
curing the  Copies  of  Maps,  Charts,  and  Books,  to  the  Authors  and  Proprietors 
of  such  Copies,  during  the  times  therein  mentioned,'  and  extending  the  bene- 
fits thereof  to  the  arts  of  designing,  engraving,  and  etching  Historical  and  other 
Prints." 

D.  CALDWELL, 
Clerk  of  the  Eastern  District  of  Pennsylvania. 


* 


TREATISE   ON  ANATOMY. 


BOOK  IV. 

PART   II. 

Organs  of  Assimilation. 
CHAPTER  I, 

OF  THE  ABDOMEN  GENERALLY. 

THE  cavity  of  the  abdomen  occupies  the  space  between  the 
inferior  surface  of  the  diaphragm  and  the  outlet  of  the  pelvis;  a 
considerable  part  of  it  is,  therefore,  withiu  the  periphery  of  the 
lower  ribs  above,  and  of  the  pelvis  below.  It  is  completely  se- 
parated from  the  cavity  of  the  thorax  by  the  diaphragm,  with 
the  exception  of  the  foramina  in  the  latter,  for  transmitting  the 
aorto,  the  ascending  cava,  and  the  oesophagus.  It  is  bounded, 
below,  by  the  iliaci  interni,  the  psoae,  and  the  levatores  ani  mus- 
cles; on  the  front  and  sides  by  the  five  pairs  of  muscles  called 
abdominal;  and  behind  by  the  lesser  muscle  of  the  diaphragm, 
the  Quadrati  Lumborum,  the  lumbar  vertebra?,  and  the  sacrum. 
The  figure  of  this  cavity  is,  therefore,  too  irregular  to  admit  of 
a  very  rigid  comparison  with  any  of  the  common  objects  of  life; 
but  a  little  reflection,  on  the  course  of  its  parietes,  will  make  it 
perfectly  understood.  It  should  be  borne  in  mind,  that  the  very 
great  projection  of  the  lumbar  vertebra?  forms  for  it  a  partial 
vertical  septum  behind;  which,  in  thin  subjects,  is  almost  in  con- 
tact with  the  linea  alba  in  front,  and  may  be  easily  distinguished 
VOL,  II.—  2  • 

' 


t>  ORGANS  OF  DIGESTION. 

through  the  parietes  of  the  abdomen,  when  the  intestines  are 
empty. 

The  abdominal  cavity  varies  only,  inconsiderably,  in  its  ver- 
tical diameter,  owing  to  the  resistance  of  the  diaphragm  above, 
and  of  the  pelvis  below ;  neither  does  it  change  behind,  owing  to 
the  resistance  of  the  spine,  the  ribs,  and  the  muscles  there.  But 
as  the  introduction  of  food,  the  development  of  gaseous  sub- 
stances during  digestion,  the  evolution  of  the  foetus,  and  many 
other  conditions,  require  some  provision  for  its  undergoing  an 
easy  augmentation  of  volume;  the  latter  occurs  principally  for- 
wards and  laterally,  by  the  yielding  of  the  muscles  and  by  the 
extension  of  their  aponeuroses.  The  diaphragm  and  the  abdo- 
minal muscles,  for  the  most  part,  act  alternately:  as  the  former 
descends  in  inspiration,  the  latter  relax  and  give  way  to  the  con- 
tents of  the  abdomen:  but  in  expiration,  the  abdominal  muscles 
contract,  and  the  diaphragm  is  pushed  upwards  by  the  viscera. 
In  attempts  at  the  expulsion  of  fasces,  and  in  parturition,  these 
muscles  contracting,  and  the  diaphragm  being  fixed  all  at  the 
same  moment,  the  cavity  of  the  abdomen  is  actually  much  di- 
minished. 

The  viscera  contained  in  the  cavity  of  the  abdomen  are  of 
three  kinds.  One  kind  is  engaged  in  digestion  and  assimilation; 
another  in  the  secretion  and  excretion  of  urine;  and  the  third  in 
generation.  As  these  viscera  are  numerous,  and  it  is  of  great  im- 
portance to  determine  with  precision  their  position  and  relative 
situation,  anatomists  are  agreed  to  divide  the  cavity  of  the  ab- 
domen into  several  arbitrary  regions.  This  is  the  more  advan- 
tageous, as  the  bony  prominences  bounding  the  abdomen  are 
not  sufficiently  numerous  and  distinct,  to  afford  those  obvious 
points  of  relation  to  the  viscera  which  they  furnish  in  other  sec- 
tions of  the  body.  To  obtain  these  regions,  consider  a  line  or 
plane  as  extending  across  the  abdomen,  about  two  inches  below 
the  umbilicus,  from  the  superior  part  of  the  crista  of  one  ilium, 
as  it  appears  through  the  skin,  to  the  corresponding  point  of  the 
other  side.  Strike  on  each  side  a  line  perpendicular  to  the  pre- 
ceding, by  commencing  at  the  lower  end  of  the  anterior  inferior 
spinous  process  of  the  ilium,  and  carrying  it  up  to  the  dia- 
phragm. Extend  a  fourth  line  across  the  abdomen  parallel  with 
the  first,  and  intersecting  the  two  last  where  they  come  upon 


OP  THE  ABDOMEN.  7 

the  cartilages  of  the  false  ribs.  It  is  evident  that  these  four 
lines  or  planes,  two  horizontal  and  two  vertical,  will,  with  the 
assistance  of  the  parietes  of  the  abdomen,  furnish  nine  regions: 
three  above;  three  in  the  middle,  and  three  below.  The  cen- 
tral region  above,  is  the  Epigastric;  and  on  its  sides  are  the 
right  and  the  left  Hypochondriac.  The  central  region  in  the 
middle,  surrounding  the  navel,  is  the  Umbilical;  and  on  its  sides 
are  the  right  and  the  left  Lumbar.  The  central  region  below, 
is  the  Hypogastric;  and  on  its  sides  are  the  right  and  the  left 
Iliac.  There  are  also  some  subordinate  divisions ;  for  example, 
the  hollow  in  the  epigastric  region,  around  the  ensiform  car- 
tilage, is  called  the  pit  of  the  stomach,  or  Scrobiculis  Cordis; 
and  for  an  inch  or  two  around  the  symphysis  pubis,  is  the  re- 
gion of  the  pubes,  (Regio  Pubis.) 

Anatomists  differ  among  themselves  about  the  points  of  de- 
parture and  the  position  of  the  lines,  or  rather  planes,  separating 
the  regions.  Some  fix  them  at  arbitrary  distances  from  the 
umbilicus,  and  others  assume  the  points  of  the  skeleton.  The 
umbilicus  is  the  most  fallacious  mark,  because  its  elevation  va- 
ries considerably,  according  to  the  state  of  distention  of  the  ab- 
domen, it  being  comparatively  higher  when  the  abdomen  is 
tumid  than  when  it  is  not.  Neither  does  it  answer  to  take  the 
anterior  ends  of  the  last  ribs  as  the  points  for  the  upper  horizon- 
tal line  to  pass  through;  as  they,  sometimes,  are  almost  as  low 
down  as  the  umbilicus  itself.  The  superior  anterior  spinous 
processes  are  also  objectionable  as  the  points  of  departure  for 
the  vertical  lines;  as  they  leave  too  much  room  for  the  central 
regions  of  the  abdomen,  and  too  little  for  the  lateral:  I  have, 
therefore,  after  some  hesitation,  thought  proper  to  substitute  the 
anterior  inferior  spinous  processes;  and,  especially,  as  the  posi- 
tion of  the  viscera,  as  almost  universally  described,  is  more  in 
accordance  with  this  rule. 

General  Situation  of  the  Viscera  of  the  Mdomen. 

When  the  abdomen  is  so  opened  as  to  leave  its  viscera  in 
their  natural  position,  they  will  be  found  as  follows: — 

1.  The  Liver,  the  largest  gland  of  the  body,  is  in  the  right 


ORGANS  OF  DIGESTION. 

upper  part  of  the  abdomen,  immediately  below  the  diaphragm. 
It  occupies  nearly  the  whole  of  the  right  hypochondriac  region; 
the  upper  half  of  the  epigastric;  and  the  right  superior  part  of 
the  left  hypochondriac.  The  anterior  extremity  of  the  gall- 
bladder projects  beyond  its  anterior  margin. 

2.  The  Spleen  is  situated  in  the  posterior  part  of  the  left  hy- 
pochondriac region. 

3.  The  Stomach,  in  a  moderate  condition  of  distention,  occu- 
pies the  lower  half  of  the  epigastric  region,  and  the  right  infe- 
rior portion  of  the  left  hypochondriac. 

4.  The  Smaller  Intestine,  when  moderately  distended   by 
flatus,  occupies  the  umbilical  region,  the  hypogastric,  portions 
of  the  iliac  on  each  side,  and  also  the  upper  part  of  the  cavity 
of  the  pelvis,  when  the  viscera  of  the  latter  are  empty. 

5.  The  Large  Intestine  traverses  the  cavity  of  the  abdomen 
in  such  manner  as  to  perform  almost  the  entire  circuit  of  it 
It  begins  in  the  right  iliac  region  by  receiving  the  lower  extre- 
mity of  the  small  intestine;  it  then  ascends  through  the  right 
lumbar  and  the  right  hypochondriac,  passes  into  the  lower  part 
of  the  epigastric,  or  into  the  upper  of  the  umbilical,  according 
to  the  state  of  distention  of  the  stomach;  thence  it  gets  into  the 
left  hypochondriac,  being  fixed  higher  up  there  than  in  the  cor- 
responding-region of  the  other  side;  afterwards  it  goes  down 
into  the  left  lumbar  and  into  the  left  iliac;  thence  it  passes  into 
the  pelvis,  and,  descending  in  front  of  the  sacrum,  terminates 
in  the  orifice  called  anus. 

6.  The  Caul,  or  Omentum,  is  a  membrane,  of  various  densi- 
ties, in  different  individuals,  and  lies  in  front  of  the  intestines. 
Sometimes  it  is  found  spread  ovsr  the  latter  like  an  apron,  but 
on  other  occasions  is  drawn  up  into  the  umbilical  region,  form- 
ing a  ridge  across  it. 

7.  The  Pancreas  lies  transversely  in  the  lower  back  part  of 
the  epigastric  region.     It  extends  from  the  left  hypochondriac 


OP  THE  ABDOMEN.  9 

region  to  the  right  side  of  the  spine,  and  is  placed  behind  the 
stomach,  so  as  to  be  covered  by  it. 

8.  The  Kidneys  and  the  Capsulse  Renales,  two  in  number 
each,  are  placed  in  the  posterior  part  of  the  lumbar  region  on 
the  side  of  the  spine. 

9.  The  Urinary  Bladder  and  the  Rectum,  in  the  male,  occupy 
the  cavity  of  the  pelvis,  and  in  the  female  between  them  are 
placed  the  uterus,  the  ovaries,  and  the  vagina. 

As,  in  the  dissection  of  the  abdominal  viscera,  the  subject  is 
commonly  placed  on  its  back,  so  the  preceding  description  is 
made  out  with  a  strict  reference  to  that  position.  Some  modi- 
fication in  the  shape  of  the  abdomen,  as  well  as  in  the  situation 
of  its  contents,  occurs  in  standing  upright.  The  front  of  the 
abdomen  becomes  more  protuberant,  the  lumbar  vertebra  make 
a  greater  projection  forwards.  The  pelvis  is  so  adjusted,  in 
order  to  bring  the  acetabula  directly  in  the  line  of  support  to 
the  spine,  that  the  convexity  of  the  sacrum  presents  almost  up- 
wards, and  the  superior  straight  loolts  forwards  and  upwards 
towards  the  navel,  so  that  much  of  the  weight  of  the  viscera  is 
thrown  upon  the  pubes.  In  this  attitude  most  of  the  viscera 
descend,  but  more  obviously  the  liver,  from  its  weight,  size,  and 
solidity.  Portal  has  verified  this  descent  by  comparing  the 
thrusts  of  poniards  into  the  liver  in  the  erect,  with  those  inflict- 
ed in  the  horizontal  position.  He  also  asserts  that  the  same 
may  be  ascertained  in  the  living  body  by  applying  the  fingers 
under  the  false  ribs,  and  then  directing  the  person  to  change 
from  the  recumbent  into  the  vertical  position.  The  spleen  af- 
fords the  same  results  when  it  is  slightly  enlarged,  and  the  de- 
scent of  the  liver  and  spleen  will  of  course  ensure  that  of  the 
stomach  and  intestines.  According  to  Winslow,  the  pain  and 
faintness  which  are  felt  after  a  long  abstinence,  come  from  the 
vacuity  of  the  stomach  and  intestines,  which  thereby  withdraw 
their  support  from  the  liver,  and  permit  it  to  drag  upon  the 
diaphragm. 

The  presence  of  flatus  in  the  stomach  and  intestinal  canal, 
seems  to  be  entirely  natural  to  them;  for  it  is  comparatively 


10  ORGANS  OF  DIGESTION. 

rare  to  find  them  destitute  of  it,  even  when  they  contain  no 
food  or  faeces.  The  large  intestine  is,  however,  more  frequent- 
ly found  contracted  or  empty  than  the  small.  Owing  to  the 
flexible  character  of  a  considerable  portion  of  the  abdominal  pa- 
rietes,  the  latter,  by  their  own  contraction,  as  well  as  by  atmo- 
spheric pressure,  are  kept  in  close  contact  with  the  viscera;  and 
the  viscera  again,  by  the  same  influence,  are  kept  in  close  con- 
tact with  one  another;  so  that,  notwithstanding  the  irregularity 
of  their  forms  and  the  fluctuating  size  of  the  hollow  ones,  there 
is  no  unoccupied  space  in  the  cavity  of  the  belly. 

Several  instances  are  reported  by  anatomists,  in  which  a  to- 
tal transposition  of  the  abdominal  viscera  has  occurred,  so  that 
those  which  belonged  to  the  right  side  were  placed  in  the  left* 
They  are,  however,  exceedingly  rare:  in  probably  more  than 
fifteen  hundred  observations,  or  more,  I  have  never  met  with 
one  instance  of  it. 


CHAPTER  II. 

OF  THE  PERITONEUM,  AND  SEROUS  MEMBRANES,  GENERALLY. 
SECT.  I. OF  THE  PERITONEUM. 

THE  sides  of  the  abdomen  are  lined,  and  its  viscera  are  co- 
vered by  a  membrane  called  Peritoneum.f  As  the  reflections  of 
this  membrane,  by  being  thrown  over  the  periphery  of  almost 
every  viscus  of  the  abdomen,  consequently,  assume  the  same 
shape ;  and  as  it  lines,  without  exception,  the  interior  surface  of 
every  part  of  the  abdomen,  its  form  is  extremely  complicated, 
and  can  only  be  judged  of  accurately  after  the  study  of  the 
viscera  is  completed.  For  the  present  it  will  only  be  neces- 
sary to  give  the  outline  of  it,  leaving  the  details  to  each  appro- 
priate occasion. 

*  Portal,  Haller,  Sandifort,  &c. 

f  From  5«e/T«/v»<r6*/  quod  est  circumquaque  extend!. 


OF  THE  PERITONEUM.  11 

In  man,  it  is  a  complete  sac,  having  no  hole  in  it;  but  in  wo- 
man, its  cavity  communicates  externally  through  the  Fallopian 
tubes.  It  has  a  double  use:  In  consequence  of  covering  the 
viscera,  it  is  so  reflected  from  them  to  the  sides  of  the  abdomen, 
that  its  processes  keep  the  viscera  in  their  proper  places,  and, 
therefore,  answer  as  ligaments:  again,  its  internal  surface  being 
smooth,  indeed,  highly  polished,  and  continually  lubricated  by  a 
thin,  albuminous  fluid,  corresponding  with  the  synovial  mem- 
brane of  the  joints,  the  motions  which  the  viscera  have  upon 
each  other  in  exercise,  and  in  the  peristaltic  movements  of  the 
bowels,  are  much  facilitated. 

The  manner  in  which  a  double  night-cap  is  applied  to  the 
head,  will  afford  the  easiest  conception  of  the  reflections  of  the 
peritoneum.  If  there  were  only  one  viscus  in  the  belly,  and  that 
of  a  somewhat  regular  outline,  as  the  spleen,  the  comparison 
would  be  rigid,  and  perfectly  appreciable.  One  part  of  the  cap 
is  close  to  the  head,  and  compares  with  the  peritoneal  coat  of 
the  spleen ;  the  other  is  loose,  and  is  equivalent  to  the  peritoneum, 
where  it  is  in  contact  with  the  parietes  of  the  belly.  It  is  also 
evident  from  this,  that  none  of  the  viscera  can  be  said  to  be 
within  the  cavity  of  the  peritoneum ;  that  they  are  all  on  its  out- 
side; and  that  a  viscus,  in  getting  a  coat  from  the  peritoneum, 
merely  makes  a  protrusion  into  its  cavity.  Starting  with  this 
simple  proposition,  it  is  easy  to  conceive  of  a  second,  a  third  body, 
and  so  on,  deriving  an  external  coat  from  a  protrusion  into  the 
same  sac.  Admitting  these  bodies  to  be  spheres,  the  proposition 
is  immediately  intelligible;  and,  as  a  last  step  from  it,  the  idea  is 
not  rendered  much  more  complex  by  substituting  any  bodies  even 
the  most  irregular  in  form,  for  these  spheres. 

Such,  then,  is  the  fact  in  regard  to  the  stomach,  intestines,  &c.; 
they  all,  with  exceptions  to  be  stated,  derive  an  external  coat 
from  the  peritoneum. 

The  Peritoneum  is,  for  the  most  part,  smoothly  spread  upon 
the  interior  surface  of  the  abdominal  muscles.  It  adheres  to 
them  with  considerable  firmness  by  means  of  intervening  cellular 
substance :  this  adhesion,  where  it  closes  the  posterior  opening  of 
the  umbilicus,  is  unusually  strong.  Below,  the  uniformity  of  the 
membrane  as  it  descends  from  the  navel  to  the  pelvis  is  inter- 
rupted by  its  being  reflected  over  the  urachus,  and  over  the  re- 


12  ORGANS  OF  DIGESTION. 

mains  of  the  umbilical  artery  on  each  side.  Where  the  urachus 
is,  it  forms  an  oblong  prominent  ridge,  reaching  to  the  upper  ex- 
tremity of  the  bladder;  and,  as  regards  each  umbilical  artery, 
the  duplicature  is  of  variable  breadths  in  different  individuals; 
but  always  forms  a  well  marked  falciform  process,  reaching 
from  near  the  umbilicus  to  the  lower  side  of  the  bladder,  and  di- 
viding the  inguinal  region  into  two  parts  or  fossae,  one  next  to 
the  pubes,  and  the  other  nearer  to  the  ilium.  In  the  undistended 
state  of  the  bladder  the  peritoneum  reaches  to  the  pubes,  is  re- 
flected from  the  latter  to  the  upper,  and  then  goes  over  the  pos- 
terior surface  of  the  bladder.  In  the  male,  it  goes  from  the  pos- 
terior lower  end  of  the  bladder  to  the  rectum,  but,  in  the  female, 
it  does  not  descend  so  low  there,  and  passes  from  the  bladder  to 
the  vagina  and  uterus,  and  afterwards  to  the  rectum. 

In  the  concavity  of  the  ilium,  and  in  the  lumbar  region,  the 
peritoneum  is  attached  by  long  loose  cellular  substance,  which 
permits  it  to  be  stripped  off  easily,  simply*  by  tearing.  In  these 
several  regions  it  encounters  the  colon,  over  which  it  is  reflected, 
and.  thereby  forms  the  Mesocolon ;  thence  it  passes  in  front  of 
the  kidneys,  but  separated  from  them  by  a  thick  layer  of  cellu- 
lar and  adipose  matter,  and  immediately  afterward  it  is  thrown 
into  a  long  duplicature,  extending  obliquely  across  the  lumbar 
vertebras  from  above,  downwards,  and  to  the  right  side.  This 
duplicature  includes  the  small  intestine,  and  is  the  Mesentery. 

In  the  highest  regions  of  the  abdomen,  the  peritoneum  is  in  the 
greater  part  of  its  extent  uniformly  reflected  over  the  concave 
surface  of  the  diaphragm,  and  adheres  so  closely  to  it,  as  to  re- 
quire a  cautious  and  protracted  dissection  for  its  entire  removal. 
As  the  remains  of  the  umbilical  vein  of  the  fetus  are  still  found, 
but  in  a  ligamentous  condition,  going  from  the  navel  to  the  under 
surface  of  the  liver,  their  existence  gives  rise  to  a  broad  falciform 
duplicature  of  peritoneum,  which  passes  from  the  upper  half  of 
the  linea  alba  and  from  the  middle  line  of  the  diaphragm  to  the 
liver.  Another  line  of  attachment,  or  of  reflection,  of  this  mem- 
brane to  the  liver,  is  found  all  along  the  posterior  margin  of  the 
latter.  In  the  same  region,  it  is  also  reflected  from  the  diaphragm 
to  the  spleen  and  to  the  stomach.  Such  is  the  general  account 
of  the  course  of  the  peritoneum.  Each  of  the  duplications  has  a 
distinct  name,  and  some  peculiarity  of  organization  or  of  relation, 


OP  THE  OMENTA.  13 

"which  will  require  a  specific  description  and  a  frequent  allusion 
to  it. 

It  is  proved,  from  what  has  been  said,  that  the  peritoneum  is 
a  single  and  complete  sac,  and  that,  with  the  exception  stated  of 
the  Fallopian  tubes,  there  is  no  hole  in  it  either  for  the  passing 
of  blood  vessels,  nerves,  or  viscera.  And  that  it  is  so  folded  over 
the  abdominal  viscera,  that  with  patience  and  sufficient  address, 
one  might  remove  it  from  their  surface  and  extract  them,  with- 
out even  laying  open  its  cavity :  an  experiment  said  to  have  been 
successfully  accomplished  by  Nicholas  Massa,*  and  some  other 
anatomists. 

SECT.   II. — OF  THE  OMENTA. 

There  are  four  processes  of  the  peritoneum,  each  of  which  is 
designated  under  the  term  Omentum,  Epiploon,  or  Caul. 

1.  The  Omentum  Minus  or  the  Hepatico-Gastricum,  extends, 
as  its  name  imports,  between  the  liver  and  the  stomach.  It  be- 
gins at  the  transverse  fissure  of  the  liver,  and  proceeds  from  it, 
from  the  right  side  of  the  lobulus  spigelii,  the  front  of  which  it 
conceals,  and  from  the  inferior  posterior  face  of  the  tendinous 
centre  of  the  diaphragm;  it  is  attached  to  the  lesser  curvature  of 
the  stomach  in  all  the  space  between  the  cardiac  and  the  pylo- 
ric  orifices.  Its  right  margin  reaches  beyond  the  pylorus  to  the 
duodenum,  and  includes  the  vessels  going  to  the  liver,  and  the 
biliary  ducts ;  in  consequence  of  which,  this  margin  is  called  the 
Capsule  of  Glisson.  The  capsule  is,  however,  more  properly  the 
condensed  cellular  substance  within. 

The  two  laminae  which  compose  it  are  thin  and  transparent, 
and  have  but  little  fat  in  them*;  in  approaching  the  stomach  they 
become  very  distinct  from  each  other,  and  receive  between  them 
the  superior  coronary  vessels  of  the  stomach.  One  lamina  then 
goes  before  the  stomach  and  the  other  behind,  in  the  form  of  a 
peritoneal  covering.  These  laminae,  having  covered  in  that  way 
the  anterior  and  the  posterior  surface  of  the  stomach,  unite  again 
on  the  greater  curvature  of  the  latter,  to  form  the  beginning  of 
the  omentum  majus. 

*  Atiat.  Liber.  Introdact.  an.  1539.  Portal. 
VOL.  II.— 3 


14  ORGANS  OF  DIGESTION. 

2.  The  Omentum  Majus  or  Gastro-Colicum,  as  indicated  by  its 
name,  is  connected  at  one  end  all  along  the  greater  curvature  of 
the  stomach,  and  by  the  other  along  the  transverse  part  of  the 
colon.      As  it  commences    by   two  laminae,  so  it  is  continued 
throughout  in  the  same  way.     It  is  commonly  found  more  or  less 
spread  on  the  front  surface  of  the  small  intestines,  but  occasion- 
ally it  is  tucked  up  in  the  epigastric  region.     When  fairly  spread 
out,  either  naturally  or  artificially,  its  course  will  be  found  as  fol- 
lows :     It  first  of  all  descends  from  the  stomach  to  the  pelvis ;  it 
then  turns  upwards,  so  as  to  reverse  its  course,  and  continues  to 
ascend  till  it  reaches  the  colon.    Its  two  laminae  then  separate  and 
receive  the  colon  between  them,  so  that,  in  this  respect,  the  ar- 
rangement is  entirely  comformable  to  what  happens  to  the  sto- 
mach.     The  subsequent  continuation    of  these  laminae   is  the 
mesocolon,  which  will  be  more  particularly  described. 

As  the  omen  turn  majus  consists  of  two  laminae  in  its  whole  ex- 
tent, it  is  clear  that  it  resembles  a  flattened  bag  lined  by  another 
bag;  so  that  in  its  whole  thickness,  when  held  between  the  fin- 
gers, there  are  four  laminae.  It  is  an  irregular  quadrilateral 
membrane,  which,  in  corpulent  subjects,  is  interspersed  with  a 
great  deal  of  fat ;  but  in  such  as  are  emaciated,  it  is  wholly  des- 
titute of  the  latter ;  and  instead  of  being  entire  in  its  parietes  is  a 
delicate  reticulated  membrane,  so  that  the  rule  about  the  integ- 
rity of  the  peritoneum  is  not  fully  accurate  as  applied  to  this  sec- 
tion of  it.  On  the  right  side  it  is  continuous  with  the  omentum 
colicum,  and  on  the  left  with  the  omentum  gastro-splenicum. 

3.  The  Omentum  Colicum  may  be  considered  as  a  continuation 
of  the  omentum  majus  along  the  ascending  and  a  part  of  the 
transverse  colon.     In  some  rare  fases,  (for  in  my  own  observa- 
tions I  have  not  met  with  the  arrangement,)  its  origin  is  conti- 
nued downwards  to  the  coecum,  and  at  its  left  margin  is  extended 
along  the  transverse  colon  to  the  spleen.     Much  more  commonly 
it  is,  as  stated,  simply  an  appendage  of  the  great  omentum,  or  its 
right  flank,  advancing  for  a  short  distance  along  the  ascending 
colon. 

It  consists  of  but  two  laminae  in  all,  commonly  containing  fat, 
but  in  this  respect  subject  to  the  same  rule  as.  the  omentum 
majus. 


OF  THE  OMfiNTA.  15 

4.  The  Omentum  Gastro-Splenicum  is  the  left  flank  or  mar- 
gin of  the  omentum  majus,  extended  from  the  great  end  of  the 
stomach  to  the  spleen.  It  of  course  consists  of  but  two  laminae, 
which  contain  between  them  the  splenic  vessels  and  the  vasa 
brevia. 

By  looking  for  the  posterior  end  of  the  gall-bladder,  and  then 
passing  a  finger  under  the  right  margin  of  the  hepatico-gastric 
omentum,  or,  in  other  words,  under  the  capsule  of  Glisson,  where 
it  extends  from  the  liver  to  the  duodenum,  the  finger  will  be 
found  to  have  insinuated  itself  behind  the  stomach,  and,  by  be- 
ing directed  downwards,  will  be  thrust  into  the  sac  or  cavity  of 
the  great  omentum.  In  children,  where  the  latter  is  less  reticu- 
lated than  in  adults,  and  consequently  more  entire,  a  large  blow- 
pipe introduced  at  the  same  point  will  enable  one  to  inflate  this 
cavity,  and  to  separate  its  anterior  from  its  posterior  wall.  This 
aperture,  called  the  foramen  of  Winslow,  is  the  route  by  which 
the  internal  or  lining  lamina  of  the  omentum  majus  is  introduced, 
so  as  to  make  this  process  of  peritoneum  double  throughout 
its  whole  parietes.  Though  this  fact  of  duplicity  is  generally 
conceded,  no  author  heretofore,  to  my  knowledge,  has  pointed 
out  satisfactorily  the  means ;  and  for  the  suggestion  of  it,  I  am 
indebted  to  a  learned  and  zealous  member  of  the  profession, 
now  Professor  Hodge  of  the  University.  Struck,  at  an  early  pe- 
riod of  his  studies,  with  the  difficulty  of  tracing  a  double  sac  to 
the  omentum  majus,  out  of  a  single  membrane  of  the  peritoneum, 
this  suggestion  was  happily  made  by  him  to  remove  the  difficul- 
ties of  other  explanations.  An  attempt  at  a  diagram  formed 
upon  any  other  principle  I  have  invariably  seen  to  fail.  If  the 
reader  has  conceived  the  idea,  the  inference  will  be  plain,  that 
the  lining  lamina  of  the  omentum  majus  is  continued  as  a  com- 
mon peritoneal  covering  over  the  posterior  face  of  the  stomach, 
and  then  forms  the  posterior  lamina  of  the  hepatico-gastric  omen- 
tum. It  will  also  be  plain  that  the  same  lamina,  having  reached 
the  colon  in  its  return,  continues  afterwards  as  the  upper  lamina 
of  the  transverse  mesocolon. 

From  what  has  been  said  concerning  the  general  qualities  of 
the  peritoneum,  it  is  to  be  understood  that  though  it  enjoys  much 
power  of  gradual'  extension,  nevertheless  this  quality  is  not  suf- 


16  ORGANS  OF  DIGESTION. 

ficient  to  enable  it  to  endure,  without  a  special  provision,  the 
sudden  and  extensive  dilatations  to  which  the  stomach  and  bow- 
els are  exposed,  from  the  introduction  of  food  and  from  the  evo- 
lution of  gases  during  digestion.   Of  all  the  coats  of  these  organs, 
it  is  the  least  extensible  and  contractile;  its  rupture,  therefore, 
is  guarded  against  by  one  invariable  rule.     For  example:  as 
the  muscular  and  other  coats  of  the  stomach  dilate,  the  perito- 
neum is  drawn  from  the  omentum  minus  and  majus  to  cover  the 
stomach;  therefore,  as  the  stomach  enlarges,  the  omenta  dimi- 
nish: and  as  the  stomach  decreases,  the  omenta,  by  the  restora- 
tion of  peritoneum,  resume  their  primitive  size.     In  this  way  the 
uterus,  notwithstanding  its  great  augmentation  in  the  progress 
of  pregnancy,  still  keeps  itself  covered  by  peritoneum,  from  the 
ability  of  the  latter,  as  mentioned,  to  slide  from  one  part  and  to 
apply  itself  to  another.     The  true  intention,  then,  of  the  appa- 
rently useless  length  of  many  processes  of  the  peritoneum,  is 
explained,  by  their  being  a  provision  for  the  augmentation  of 
the  hollow  viscera  of  the  abdomen,  in  the  discharge  of  their  na- 
tural functions.     Adopting  this  explanation  as  the  basis  of  our 
observations,  we  shall  find  that  according  to  the  probable  or 
even  possible  augmentation  of  a  viscus,  so  are  its  peritoneal  at- 
tachments.    The  stomach,  which  next  to  the  uterus  enlarges 
more  than  any  other  viscus,  gets  its  subsidiary  supply  of  perito- 
neum from  the  length  of  the  omentum  minus  and  majus;  the 
colon,  which  is  next  in  order,  is  supplied  from  the  length  of  its 
mesocolon ;  the  small  intestines,  which  are  next,  from  the  length 
of  the  mesentery.     The  latter,  however,  would  be  too  long  for 
that  simple  purpose ;  but  the  objection  is  removed  by  recollect- 
ing that  the  mesentery  has  also  to   accommodate   numerous 
chains  of  lacteal  glands,  through'-which  the  chyle  must  pass  in 
its  elaboration,  before  it  is  fit  to  enter  into  the  general  circula- 
tion.    The  liver,  being  of  a  size  almost  stationary,  has  its  peri- 
toneal attachments  proportionally  short;  and  its  peritoneal  co- 
vering, from  the  shortness  of  the  connecting  cellular  substance, 
is  disqualified  from  sliding.     The  spleen  is  in  the  same  predica- 
ment with  the  liver,  except  that  its  size  is  not  stationary;  but,  in 
this  case,  the  peritoneum  presents  a  phenomenon  entirely  re- 
markable :  it  wrinkles  upon  the  contraction  of  the  spleen. 

If  this  mode  of  reasoning,  derived  from  an  arrangement  of 


OF    THE  OMENTA.  17 

parts  which -no  one  denies,  be  correct,  it  follows  that  physiolo- 
gists have  erred  sadly  in  the  supposed  uses  of  the  omentum  ma- 
jus.     That  this  organ  is,  in. fact,  only  subsidiary  to  the  enlarge- 
ment of  the  stomach  and  colon,  so  as  to  prevent  the  rupture  of 
their  peritoneal  coat,  and  that  it  is  neither  intended  to  keep  the 
belly  warm,  as  so  learned  a  naturalist  as  'M.  G.  Cuvier  has  sug- 
gested;* nor  is  it  a  special  store-house  for  the  wants  of  the  sys- 
tem during  the  destitution  of  other  aliment,  farther  than  adipose 
matter  in  other  parts -of  the  body  is.t     In  regard  to  the  first  theo- 
ry, it  does  not  appear  that  the  inhabitants  of  cold  climates  are 
better  furnished  with  an  omentum  majus  than  those  of  the  torrid 
zone :  that  it  is  better  developed  in  winter  than  it  is  in  summer ; 
that  it  is  tucked  up  in  warm  weather  to  cool  the  intestines,  or 
spread  out  in  cold  weather  to  make  them  more  comfortable.   On 
the  contrary,  it  is  ascertained  that  its  position  is  variable  at  all 
seasons;  that  in  the  coldest  of  weather  it  is  as  often  found  col- 
lected in  the  epigastric  region,  or  to  one  side  of  the  abdomen,  as 
it  is  in  the  warmest;  consequently,  its  position  is  the  result  of 
whatever  motions  may,  for  the  time,  have  been  impressed  upon 
it  by  the  distention  of  the  stomach,  and  by  the  peristaltic  move- 
ments of  the  bowels.     In  regard  to  the  theory  of  Dr.  Rush,  the 
objection  is  insurmountable,  that  children,  who  are  equally,  if  not 
more  exposed  to  starvation  and  sickness  than  adults,  never  have 
fat,  except  in  very  small  quantities,  in  the  omentum,  and  that 
only  along  the  course  of  its  vessels.     The  fat  is,  therefore,  not  to 
be  viewed  as  an  essential  circumstance  in  the  structure  of  the 
omentum,  as  all  children  and  many  adults  have  it  only  very 
sparingly;  for  the  omentum  being  wanted  as  a  membrane  of 
reserve  to  the  stomach  and  colon,  the  deposite  of  fat  in  it,  is  in 
obedience  to  one  of  the  general  laws  of  the  system,  whereby  the 
cellular  substance  beneath  the  serous  membranes  is  disposed  to 
secrete  fat  as  the  individual  advances  in  life ;  which  is  exempli- 
fied on  the  heart  and  in  the  pleura.     Another  .argument  is,  that 
in  the  ruminating  animals,  where  there  are  four  stomachs,  and 
from  the  vegetable  nature  of  their  aliment  these  stomachs  must, 
in  the  course  of  digestion,  be  very  much  distended,  the  great 
omentum  is  of  proportionate  magnitude.f 

*  XXII.  Lecon  D'AnaJt.  Comp. 

f  An  Inquiry  into  the  Uses  of  the  Omentum,  by  James  Rush,  Philad.  1809. 

t  Cuvier,  XXII.  Legon,  loc.  cit. 


18  ORGANS  OF   DIGESTION. 

As  occurs  in  other  parts  of  the  body,  also,  the  fat  of  the  omen- 
turn  accumulates  in  animals  that  take  but  little  exercise,  while  it 
is  very  deficient 'in  such  as  lead  an  active  life. 

I  am  induced  to  believe  that  the  hard  knots  felt  in  the  abdo- 
men of  such  persons  as  suffer  from  abdominal  affections,  fre- 
quently depend  upon  the  accumulations  of  the  omentum  majus 
at  particular  but  variable  points. 


SECT.  III. GENERAL  ANATOMY  OF  THE  SEROUS  MEMBRANES. 

As  the  peritoneum  presents  one  of  the  best  examples  of  a  nu- 
merous class  of  membranes,  called  SEROUS,  it  will  be  useful  at 
this  point  to  inquire  into  their  general  condition  and  properties. 
They  are,  for  the  most  part,  thin,  and  strongly  resemble  com- 
pressed cellular  membrane ;  having  been,  indeed,  by  some  ana- 
tomists, considered  as  such.  They  invariably  assume  the  form 
of  perfect  sacs,  and  as  they  are  found  in  alt  parts  of  the  body, 
they  are  kept  distinct  from  each  other.  The  arachnoid  mem- 
brane of  the  brain,  the  pericardium,  the  pleura,  the  sy  no  vial 
membranes  of  the  joints,  the  bursae  mucosae  of  tendons,  the  peri- 
toneum, and  the  tunica  vaginalis  testis,  belong  to  this  class. 
They  are  not  all  of  the  same  thickness,  as  some  are  much  more 
dense  than  others ;  they  adhere  to  neighbouring  parts  by  a  la- 
mina of  cellular  substance,  which  is  also  of  variable  thickness 
and  ductility ;  indeed,  on  some  occasions,  it  is  not  entirely  dis- 
tinct, from  its  extreme  shortness  and  tenuity. 

As  the  serous  membranes  are  only  displayed  over  the  surface 
of  the  organs  which  they  cover,  after  the  manner  of  a  double 
night-cap  drawn  over  the  head ;  their  cavity  always  remains  en- 
tire, notwithstanding  it  is  variously  modified  by  the  shape  of  the 
organs  protruded  into  it ;  and  has  its  parietes  in  contact,  owing 
to  external  compression.  They  are  entirely  distinct  from  the 
essential  structure  of  the  organs  covered,  and  are  displayed  over 
those  of  thfc  most  dissimilar  functions,  as,  for  example,  the  intes- 
tines and  the  liver.  A  sac  of  this  description,  then,  is  of  infinite 
importance  in  establishing  between  organs  which  border  upon 
one  another  a  strong  partition :  and,  consequently*  in  warding  off 
any  injurious  influence  which  their  dissimilar  natures  would 


ANATOMY  OF  SEROUS  MEMBRANES.  19 

otherwise  cause  them  to  have  upon  each  other.  Important  or- 
gans are,  therefore,  invariably  thus  insulated,  so  that  whether  in 
a  healthy  or  in  a  diseased  state,  their  actions  are  carried  on 
within  themselves ;  and  not  only  so,  but  it  is  even  possible,  and, 
indeed,  is  found  in  morbid  dissections,  every  day,  that  an  organ 
may  be  diseased  while  its  serous  covering  is  unaffected ;  or  the 
reverse.  Thus,  we  have  large  suppurations  in  the  liver,  while  its 
peritoneal  coat  is  healthy ;  large  accumulations  of  water  in  the 
tunica  vaginalis  testis,  while  the  testicle  itself  is  sound ;  in  the 
thorax,  with  sound  lungs  and  heart ;  in  the  abdomen,  with  vis- 
cera generally  sound ;  in  the  joints,  without  an  affection  of  the 
bones.  Nothing  is  more  common  than  to  see  partial  adhesions, 
the  result  of  inflammation,  causing  the  opposite  sides  of  these 
sacs  to  adhere,  without  any  evident  constitutional  or  visceral 
derangement ;  and  some  of  our  plans  of  cure,  as  in  the  hydro- 
cele,  are  founded  upon  this  well  established  fact. 

The  serous  membranes  are  throughout  thin,  transparent, 
and  white :  in  some  points  their  tenuity  is  so  extreme  that  they 
seem  to  consist  simply  in  a  smooth,  polished  surface,  spread 
over  parts ;  this  is  strikingly  the  case  on  the  interior  face  of  the 
dura  mater,  on  the  ventricles  of  the  brain,  and  on  the  cartilages 
of  the  joints.  The  evidence  of  their  extension  there,  is  conse- 
quently derived  principally  from  induction;  and  .from  morbid 
alteration,  in  which  they  become  thickened.  Their  internal 
surface,  in  a  natural  state,  is  always  smooth,  highly  polished, 
shining ;  and,  being  also  lubricated  by  its  peculiar  unctuous  se- 
cretion, the  opposite  parietes,  when  they  come  into  contact, 
glide  freely  upon  each  other ;  a  circumstance  indispensable  to 
the  free  action  of  the  joints,  and  to  the  peristaltic  motion  of  the 
bowels.  Bordeu  has  asserted,  that  these  remarkable  characters 
of  the  serous  membranes  depend  upon  the  compression  and  the 
friction  to  which  they  are  continually  exposed :  but  to  this  opi- 
nion the  argument  of  Bichat  is  unanswerable,  that  in  their  ear- 
liest observable  period  in  the  foetus  they  have  the  same  polish. 

The  fluid  secreted  from  the  serous  membranes  resembles, 
strongly,  the  serosity  of  the  blood.  It  is  poured  out  continually 
by  the  exhalent  orifices,  and  in  a  short  time  afterwards  is  taken 
up  by  the  absorbents ;  so  that  in  a  natural  state  there  is  seldom 
more  than  sufficient  to  lubricate  the  surfaces  of  the  membrane. 


20  ORGANS  OF  DIGESTION. 

When  the  abdomen  of  an  animal  recently  killed  is  exposed  to  the 
air,  this  fluid  rises  in  the  form  of  a  vapour.  The  several  experi- 
ments, as  the  application  of  heat,  mineral  acids,  and  so  on,  which 
prove  the  abundance  of  albumen  in  the  serum  of  the  blood,  pro- 
duce the  same  results  when  applied  to  the  secretion  from  the  se- 
rous membranes. 

The  system  of  serous  membranes  has  been  considered  by  Bi- 
chat,  and  others,  as  only  a  modification  of  cellular  membrane,  for 
the  following  reasons.  The  inflation  of  air  into  the  cellular  tis- 
sue subjacent  to  them,  reduces  them  to  the  form  of  cellular  sub- 
stance. Protracted  maceration  produces  the  same  effects  with 
more  certainty  and  precision.  When  cellular  membrane  is  in- 
flated, the  parietes  of  the  distended  cells  resemble  strongly  the 
finest  parts  of  the  serous  system,  as  the  arachnoid  membrane. 
There  is  an  identity  of  functions  and  of  affections,  for  they  are 
both  continually  engaged  in  the«great  work  of  exhalation  and  ab- 
sorption, and  suffer  in  the  same  way  from  dropsical  effusion,  with 
the  only  difference  that  the  latter  is  more  amassed  in  the  one 
than  in  the  other.  My  own  experience  goes  to  prove,  that  drop- 
sy very  seldom  manifests  itself,  to  any  extent,  in  the  cellular  tis- 
sue without  also  going  to  the  serous  cavities,  and  the  reverse. 
The  .serous  membraties  are  also  of  a  uniform  texture,  like  cellular 
substance,  and  present  no  appearance  of  fibres. 

The  serous  membranes  are  furnished  with  a  great  abundance 
of  exhalent  pores,  and  of  absorbents,  which  carry  on  their  func- 
tions with  great  activity.  They,  when  healthy,  receive  only  the 
colourless  part  of  the  blood,  whence  the  uniform  transparency  of 
these  membranes.  The  existence  of  exhalent  pores,  is  proved 
by  strangulating  a  piece  of  intestine  with  a  ligature  for  thirty-six 
or  forty-eight  hours,  when  they  become  evident,  by  dilating  them- 
selves so  as  to  receive  red  blood.  A  fine  coloured  injection  pro- 
duces the  same  result;  and  also  moistens,  by  the  escape  of  its  wa- 
tery particles,  the  surface  of  the  intestine,  by  a  very  fine  halitus 
or  dew.  The  intestine  of  a  living  animal,  if  wiped  perfectly  dry, 
will,  after  the  same  way,  soon  present  another  coat  of  serosityon 
its  surface.  The  existence  of  absorbents  to  a  great  extent  in 
them,  may  also  be  equally  well  proved,  as  they  very  readily  re- 
ceive a  mercurial  injection,  which  diffuses  itself  over  their  whole 
surface,  and  causes  them  to  have  the  appearance  of  being  formed 


ANATOMY  OF  SEROUS  MEMBRANES.  21 

entirely  of  such  vessels.  The  readiness  with  which  fluid  effused 
into  their  cavities  is  taken  up,  is  another  proof  of  the  same.  Bi- 
chat  once  saw  them  distended  with  air  in  a  man  who  had  be- 
come emphysematous  from  poisoning.  Mascagni  has  frequently 
found  them  distended  with  the  fluid  of  dropsical  collections,  which 
he  recognised  by  its  colour.  It  happened  to  the  same  anatomist 
to  find  in  two  bodies,  where  there  had  been  an  effusion  of  blood 
into  the  thorax,  the  absorbents  of  the  lungs  gorged  with  blood. 
This  faculty  of  absorption  may  sometimes  be  proved  to  continue 
for  some  hours  after  death,  by  keeping  an  animal  in  a  warm 
bath.  Mascagni  asserts,  that  he  has  witnessed  its  continuance 
for  fifteen,  thirty,  and  even  for  forty-eight  hours ;  it  is  not  impro- 
bable, however,  that  there  was  some  illusion  in  these  instances. 

It  is  more  than  probable  that  the  serous  membranes  are  en- 
tirely deprived  of  red  blood  vessels ;  the  latter  unquestionably  ex- 
ist, in  great  numbers,  on  the*exterior  surface,  where  they  creep 
through  the  cellular  substance,  but  they  may  be  removed  with 
a  scalpel  without  affecting  the  continuity  of  these  membranes. 
Again,  where  these  membranes  are  free  and  unconnected  on  both 
surfaces,  as  in  some  parts  of  the  tunica  arachnoidea,  there  is  no 
appearance  of  red  blood  vessels.  In  hernial  protrusions,  where 
there  is  a  considerable  prolapse  of  peritoneum,  the  blood  vessels 
which  are  found  abundantly  about  the  neck  of  the  sac  do  not  fol- 
low the  course  of  the  protrusion.  Unquestionably  some  commu- 
nication exists  between  the  arterial  system  and  the  serous  mem- 
branes, as  proved  by  exhalation  and  morbid  phenomena,  but  the 
mode  is  not  well  ascertained. 

In  common  hernia  and  in  dropsy,  the  serous  membranes  be- 
come more  thick :  from  my  dissections  I  am  inclined  to  think,  that 
this  change  is  not  so  great  as  is  generally  allowed ;  for  most  fre- 
quently, by  a  careful  removal  of  the  exterior  cellular  substance, 
they  have  been  restored  to  their  primitive  condition.  In  other 
cases,  as  in  large  umbilical  hernias,  they  are  so  much  attenuated 
as  to  be  found  with  difficulty. 

The  power  of  extension  which  these  membranes  possess,  is 
strikingly  marked  in  dropsical  effusions,  in  the  development  of  tu- 
mours, and  in  pregnancy ;  but  much  of  this  apparent  quality  is 
derived  from  their  mode  of  attachment  to  adjacent  parts,  where- 
by they  are  drawn  from  one  surface  to  cover  another.  This  hap- 
VOL.  II.— 4 


22  ORGANS  OF  DIGESTION. 

pens  daily  where  the  peritoneum  is  drawn  from  the  lower  part 
of  the  abdomen  to  cover  the  bladder  in  the  distentions  of  the  lat- 
ter ;  in  pregnancy,  where  it  is  drawn  upon  the  growing  uterus 
from  all  the  neighbouring  parts;  and  in  the  distentions  of  the  sto- 
mach by  food  or  flatus,  where  it  is  drawn  up  from  the  omenta. 
The  serous  membranes  have  also  a  power  of  contraction  equal  to 
that  of  their  extension  ;  but  it  should  not  be  confounded  with  that 
condition  where  they  are  simply  restored  by  the  connecting  cel- 
lular substance,  to  the  surfaces  to  which  they  originally  belonged. 
The  sensibility  of  the  serous  membranes,  from  the  want  of 
nerves  in  them,  is  extremely  obscure  in  a  natural  state,  and  only 
affords  an  imperfect  sensation  of  touch.     This  is  proved  by  the 
impunity  with  which  they  may  be  irritated  on  living  animals. 
But,  when  the  condition  of  inflammation  is  once  established,  they 
feel  the  most  acute  and  distressing  pain.     Though  they  resist 
most  frequently,  and  for  a  long  time,  disease  in  adjacent  parts, 
yet  it  not  unfrequently  is  extended  to  them  at  last.     In  such 
cases,  it  is  generally  a  local  instead  of  a  universal  affection,  which 
is  communicated  to  them :    Thus,  in  the  cancer  and  scirrhus  of 
the  uterus ;  in  disease  of  the  spleen,  and  so  on ;  the  portion  of  pe- 
ritoneum nearest  the  affected  organ  manifests  the  marks  of  the 
disease  by  preternatural  adhesions  and  by  disorganization,  with- 
out the  whole  membrane  being  involved. 

As  the  serous  system  consists  in  many. species  of  sacs,  so  each 
of  them  has  some  peculiarity  of  organization,  of  attachment,  and 
of  vital  properties,  which  is  stated  elsewhere  in  the  account  of 
the  species  themselves. 


CHAPTER  III. 

OF  THE  CHYLOPOIETIC  VISCERA. 
SECT.   I. OF  THE  STOMACH. 

THE  Stomach  ( Ventriculus,  Stomachus)  is  a  hollow  viscus, 
situated  in  the  epigastric  region,  intended  to  receive  at  one  end 


THE  STOMACH.  23 

alimentary  matters  from  the  oesophagus,  and  to  transmit  them, 
at  its  other  extremity,  after  digestion,  into  the  intestinal  tube, 
where  the  nutritious  part  of  the  food  is  absorbed  into  the  circu- 
lation. It  is  a  sort  of  conoidal  sac,  curved  considerably  up- 
wards, and  presents  two  Faces,  two  Orifices,  two  Curvatures, 
and  two  Extremities. 

The  Faces  of  the  stomach  are,  from  their  position,  named 
anterior  and  posterior,  or,  one  presents  to  the  spine  and  the 
other  towards  the  linea  alba.  The  flat  configuration  is  rendered 
more  obvious  when  the  organ  is  empty;  for  when  distended  it 
is  rounded,  and  the  anterior  face  is  caused  to  look  forwards  and 
upwards  from  the  resistance  of  the  spine  behind.  In  other 
respects  they  do  not  present  any  thing  worthy  of  particular  at- 
tention.* 

The  two  Orifices  of  the  stomach  are  named  Cardia  and  Py- 
lorus. The  first  is  at  the  left  and  most  superior  part,  but  re- 
moved to  the  distance  of  two  inches  or  more  from  the  left  ex- 
tremity. It  is  generally  considered  a  smooth  uninterrupted 
continuation  of  the  oesophagus  into  the  stomach,  immediately 
after  the  oesophagus  has  passed  through  the  diaphragm  into  the 
abdomen.  But  in  a  preparation  by  me,t  of  this  organ,  made 
by  drying,  and  now  in  the  anatomical  cabinet,  a  circular  round- 
ed pad  is  very  perceptible  at  the  cardiac  orifice;  being  elevated 
two  lines  or  more  all  around,  so  that  it  makes  a  perfect  ring  of 
from  eight  to  twelve  lines  broad  at  its  base.  This  pad  seems 
to  be  composed  of  a  cellular  substance,  which  is  almost  per- 
fectly white,  elastic,  and  consists  of  the  finest  filaments,  resem- 
bling carded  cotton:  it  is  placed  between  the  lining  membrane 
of  the  cardiac  orifice  and  the  adjoining  coat.  The  pylorus, 
when  viewed  externally,  seems  like  a  smooth  continuation  of 
the  stomach  into  the  duodenum;  but  when  felt,  there  is  a  mani- 
fest thickening  of  the  part,  depending  upon  a  structure  to  be 
presently  explained.  It  points  upwards  and  to  the  left  side, 
but  is,  by  the  whole  thickness  of  the  liver,  lower  down  than 
the  cardia. 

The  two  Curvatures  are  designated  the  great  and  small,  or 

*  In  some  cases  the  posterior  face  of  the  stomach  is  concave  to  accommodate 
it  to  the  spine :  this  is  best  seen  on  inflation  and  drying-, 
f  Made  December,  1828. 


24  ORGANS  OF  DIGESTION. 

the  upper  and  the  lower.  The  first,  forming  the  upper  margin 
of  the  stomach,  is  bounded  at  its  extremities  by  the  orifices, 
and  is  very  concave;  its  curvature  is  maintained  both  by  a  na- 
tural configuration  and  by  the  small  omentum.  The  great  cur- 
vature forms  the  whole  inferior  periphery  of  the  organ,  extend- 
ing also  from  one  orifice  to  the  other.  When  the  stomach  is 
flattened,  these  curvatures  form  very  evident  boundaries  to  the 
anterior  and  the  posterior  faces. 

The  Extremities  of  this  organ  are  singularly  disproportionate 
in  size.  That  on  the  left  forms  the  base  of  the  cone,  or  the 
large  extremity,  and  projects  considerably  beyond  the  cardia 
towards  the  spleen.  It  is  a  rounded  cul-de-sac,  or  tuberosity, 
the  dimensions  of  which  will,  of  course,  vary  according  to  the 
state  of  distention.  The  right  extremity,  on  the  contrary,  is 
produced  by  a  gradual  diminution  of  the  organ  from  its  middle 
to  the  duodenum.  When  the  stomach  has  approached  within 
an  inch  or  two  of  the  latter,  it  suffers  a  sort  of  constriction, 
which  gives  to  the  right  end  a  more  cylindrical  shape.  This 
part  is  sometimes  called  the  little  cul-de-sac,  or  the  antrum 
pylori. 

Where  the  stomach  has  been  kept  empty  for  some  time  pre- 
viously to  death,  it  is  found  not  much  larger  than  an  intestine; 
its  variable  magnitude,  therefore,  prevents  any  very  rigid  rule 
of  dimension  from  being  applied  to  it;  most  commonly,  how- 
ever, we  find  it  between  the  capaciousness  of  a  pint  and  a  quart 
measure. 

It  is  retained  in  its  situation  by  its  continuity  with  the  oeso- 
phagus and  duodenum;  also  by  the  hepatico-gastric,  and  the 
gastro-splenic  omentum.  It  is  in  contact  above,  at  its  lesser 
curvature,  with  the  diaphragm,  the  left  lobe  of  the  liver,  and 
the  lobulus  spigelii;  at  its  great  extremity  with  the  spleen,  at 
its  posterior  face  with  the  pancreas,  and  at  its  greater  curvature 
with  the  colon  and  the  mesocolon. 

The  stomach  is  formed  by  four  laminae  of  a  character  essen- 
tially differing  from  each  other:  The  Peritoneal,  the  Muscular, 
the  Nervous,  and  the  Mucous. 

The  Peritoneal  Coat  envelops  the  stomach  completely,  and 
adheres  closely,  except  at  the  curvatures,  where,  as  has  been 


THE  STOMACH.  25 

mentioned,  a  provision  is  made  for  the  dislention  of  the  organ, 
by  the  looseness  and  the  separability  of  the  attachment  of  the 
two  laminse  of  the  omen  turn  minus  and  majus.  An  uncovered 
space  will,  consequently,  be  found  between  the  lamina*  at  these 
places,  along  which  the  vessels  run  that  furnish  the  stomach. 
The  peritoneal  coat  is  very  thin,  and  is  attached  to  the  subjacent 
muscular,  by  very  fine  cellular  substance,  which  permits  it  to 
be  raised  from  the  muscular  by  a  careful  dissection. 

The  Muscular  Coat  is  intermediate  in  thickness  to  that  of  the 
intestines  and  of  the  oesophagus,  but  its  fibres  are  pale,  are  col- 
lected into  flattened  fasciculi,  and  go  in  three  directions.     The 
most  superficial  are  a  continuation  of  the  longitudinal  fibres  of 
the  oesophagus,  and  are  less  numerous  and  less  uniform  in  their 
distribution  than  the  circular  fibres.     The  greater  part  of  them 
form  a  flattened  broad  fasciculus,  which  extends  along  the  lesser 
curvature  of  the  stomach,  from  the  cardiac  to  the  pyloric  ori- 
fice.    A  thinner  and  less  distinct  fasciculus  may  be  traced  over 
the  great  cul-de-sac,  and,  somewhat  indistinctly,  along  the  great- 
er curvature,  and  a  few  others  may  be  seen  on  the  anterior  and 
posterior  faces  of  the  stomach.     The  second  series  consists  in  a 
lamina  of  circular  fibres  distinctly  covering  the  whole  surface 
of  the  organ.     They  are  not  so  numerous  near  the  cardia,  but 
become  more  abundant  as  they  are  examined  towards  the  pylo- 
rus, in  the  vicinity  of  which  they  are  multiplied  so  as  to  form 
a  lamina  of  two  lines  or  more  in  thickness.     The  circular  fibres 
are  parallel  with  each  other,  and,  when  the  stomach  is  much 
distended,  their  fasciculi  separate  so  as  to  leave  interstices  be- 
tween them  in  many  places.     The  individual  fibres  do  not  sur- 
round entirely  the  stomach,  but  are  rather  segments  of  circles. 
The  third  and  deepest  series  of  fibres  may  be  called  oblique, 
and  are  arranged  into  two  broad  flattened  fasciculi,  one  of  which 
is  placed  to  the  left  side  of  the  cardia,  and  is  prolonged  over 
the  anterior  and  the  posterior  faces  of  the  stomach;  while  the 
other,  being  to  the  right  of  the  same  orifice,  is  extended  over 
the  anterior  and  the  posterior  faces  of  the  cul-de-sac,  where  it 
supplies  the  want  of  transverse  or  circular  fibres:  they  are  con- 
sidered as  a  continuation  of  the  circular  fibres  of  the  oesophagus. 
The  Nervous  or  Cellular  Coat  connects  the  muscular  with  the 
mucous.     It  is  formed  from  a  compact,  thick,  and  short  cellular 


26  ORGANS  OF  DIGESTION. 

substance,  which  contributes  much  to  the  general  strength  of 
the  organ,  and  serves  to  conduct  the  blood  vessels  and  the 
nerves  to  the  mucous  coat. 

The  Mucous  or  Villous  Coat  is  the  most  internal,  is  not  quite 
a  line  in  thickness,  and  can  be  readily  raised  up  by  dissection. 
In  an  undistended  state  of  the  stomach  it  is  arranged  into  a 
number  of  wrinkles,  which  are  very  irregular  in  their  form, 
size,  and  direction,  but  disappear  immediately  on  distention,  or 
at  least  leave  but  very  faint  traces.  It  is  continuous  with  the 
internal  membrane  of  the  oesophagus  and  of  the  duodenum,  but 
presents  a  surface  differing  from  either  of  them,  and  which  is 
rendered  very  apparent  by  floating  it  in  water.  The  epidermis, 
which  is  continued  along  the  internal  face  of  the  oesophagus, 
ceases  around  the  cardiac  orifice,  and,  by  a  slight  maceration, 
may  be  raised  up  and  demonstrated  to  terminate  there. 

This  membrane  or  coat,  the  office  of  which  is  to  secrete  the 
gastric  juice  for  the  digestion  of  articles  of  food,  presents  a  sur- 
face that  resembles  very  much  common  velvet,  from  whence 
the  term  villous  was  applied  to  it.  It  is  common  to  find  it,  if 
examined  a  short  time  after  death,  having,  particularly  along 
the  smaller  curvature  and  at  the  great  end,  a  pink  and  some- 
times a  deeper  colour,  produced  by  an  accumulation  of  blood 
in  its  veins. 

The  texture  of  this  membrane  is  soft,  loose,  and  easily  lace- 
rated. When  floated  in  water  and  examined  with  a  magnify- 
ing glass,  it  is  found  to  have  a  superficial  honey-comb  arrange- 
ment, and  to  be  studded  with  a  multitude  of  small  follicles  or 
orifices.  In  the  vicinity  of  the  cardiac  and  of  the  pyloric  ori- 
fices, the  same  arrangement  is  more  obvious,  and  conducts  to 
some  small  muciparous  glands,  which  are  more  or  less  apparent, 
and  called  the  glands  of  Brunner. 

At  the  junction  of  the  lesser  extremity  of  the  stomach  with 
the  duodenum,  the  internal  membrane  is  thrown  into  a  circular 
duplicature  constituting  the  pyloric  valve,  and  abridging  the 
size  of  the  orifice.  It  is  seen  most  favourably  in  the  distended 
and  dried  state,  and  then  presents  a  sort  of  septum  not  unlike 
the  form  x)f  the  iris.  Around  the  external  periphery  of  this 
ring,  the  circular  muscular  fibres  have  a  sudden  augmentation 
of  number,  which  gives  them,  when  viewed  from  the  duodenum, 


INTESTINAL  CANAL.  27 

the  appearance  of  a  distinct  circular  muscle,  occasionally  called 
the  muscle  of  the  pylorus,  but  it  does  not  exist  in  a  state  so  se- 
parate as  this  name  indicates.  The  opening  of  the  valve  is  ge- 
nerally circular,  hut  sometimes  ovoidal,  and  it  is  sometimes  to 
one  side. 

It  is  very  common  to  find  the  stomach  divided  as  it  were  into 
two  compartments,  by  a  contraction  of  its  middle,  resembling 
that  of  an  hour  glass.  It  is  said  that  this  occurs  habitually 
during  digestion;  in  my  personal  observations,  however,  I  have 
seen  the  stomach  more  frequently  in  this  state  when  it  contained 
nothing,  not  even  air,  than  when  articles  of  aliment  were  in  it. 

The  stomach  is  extremely  vascular.  Its  arteries,  being 
branches  of  the  Coeliac,  are  the  Gastric,  the  Right,  and  the  Left 
Gastro-Epiploic,  and  the  Vasa  Brevia.  The  first  goes  along  its 
lesser  curvature,  the  second  and  the  third  along  its  greater  cur- 
vature, and  the  last,  from  four  to  six  in  number,  go  to  its  great 
cul-de-sac.  They  all  approach  it  between  the  laminae  of  its 
omenta,  and  undergo  many  divisions  and  subdivisions  in  the 
cellular  coat;  they  at  length  terminate  by  forming  a  very  fine 
and  delicate  vascular  arrangement  in  the  substance  of  the  mu- 
cous membrane,  and  by  being  successfully  injected  give  to  the 
latter  a  thorough  tinge  of  red.  The  veins  follow  the  course  of 
the  arteries,  and  like  them  have  frequent  anastomoses,  but  are 
larger;  they  terminate  either  directly  or  indirectly  in  the  trunk 
of  the  Vena  Portarum.  The  nerves  of  the  stomach  come  from 
the  Par  Vagum,  and  from  the  semi-lunar  ganglion  of  the  Sym- 
pathetic. Its  lymphatics  arise  from  both  the  external  and  the 
internal  surfaces,  and  their  trunks  having  to  pass  first  of  all  to 
the  lymphatic  glands,  situated  along  the  curvatures,  afterwards- 
empty  into  the  thoracic  duct. 

SECT.  II. OF  THE  INTESTINAL  CANAL. 

The  Intestinal  Canal  is  from  thirty  to  thirty-five  feet  in  length, 
and  extends  from  the  pylorus  to  the  anus.  Owing  principally 
to  a  well  marked  difference  in  magnitude,  it  is  divided  by  ana- 
tomists into  the  Small  and  into  the  Large  intestine. 


28  ORGANS  OP  DIGESTION. 


Of  the  Small  Intestine. 

The  Small  Intestine  (Intestinum  Tenue]  commences  at  the 
pylorus;  and  terminates  in  the  right  iliac  region  by  a  lateral 
aperture  into  the  large  intestine.  It  is  four-fifths  of  the  length 
of  the  whole  canal,  and  measures  from  twenty-four  to  twenty- 
eight  feet*  When  moderately  distended  its  diameter  is  about 
one  inch.  It  retains  from  one  end  to  the  other  an  uninterrupt- 
ed cylindrical  shape,  with  the  exception  that  if  the  two  ends  be 
compared,  the  upper  will  be  found  larger  than  what  is  stated  as 
the  medium  measurement,  and  the  lower  smaller;  or,  in  other 
words,  the  intestine  decreases  successively  from  above  down- 
wards, and,  as  a  whole,  is  slightly  conoidal,  though  this  diminu- 
tion is  so  gradual  that  it  is  not  perceptible  at  any  given  point. 

The  Small  Intestine,  like  the  stomach,  consists  of  four  dis- 
tinct coats,  the  peritoneal,  the  muscular,  the  cellular,  and  the 
mucous. 

The  Peritoneal  Coat  is  complete,  and  forms  the  external  sur- 
face. It  is  continued  afterwards  in  two  laminae  from  the  intes- 
tine to  the  lumbar  vertebrae,  thereby  constituting  the  Mesente- 
ry. The  two  laminae,  where  they  depart  from  the  intestine,  are 
loosely  connected  with  each  other,  for  the  purpose  of  allowing 
room  for  the  dilatation  of  the  intestine,  on  the  same  principle 
which  is  exemplified  in  regard  to  the  stomach. 

The  Muscular  Coat  is  next  to  the  peritoneal.  Its  fibres  are 
pale,  and  form  a  lamina  not  so  thick  as  common  writing  paper. 
The  superficial  ones  are  longitudinal,  not  very  distinct,  and  too 
much  separated  to  form  a  perfect  coat.  The  others  all  run  in  a 
circular  direction,  approaching  to  the  spiral,  and  are  sufficiently 
numerous  to  form  a  perfect  coat;  none  of  them  perform  a  com- 
plete circuit  of  the  intestine,  but  are  rather  segments  of  circles, 

*  This  is  the  generally  received  opinion  of  anatomists:  it  would  appear,  how- 
ever, to  be  applicable  only  when  the  intestine  is  left  attached  to  the  mesentery; 
for  if  it  be  cut  off  and  straightened,  it  will  measure  thirty-four  feet,  which,  added 
to  eight  feet  of  large  intestine  treated  in  the  same  way,  will  amount  in  all  to  forty- 
two  feet.  If  to  the  estimate  of  this  length  we  add  what  is  lost  by  the  doublings 
of  the  mucous  coat,  the  entire  length  of  surface  must  amount  to  nearly  sixty  feet, 
at  least,  in  many  subjects. 


INTESTINAL  CANAL.  29 

This  coat  is  united  to  the  peritoneal  by  a  thin  scattered  cellular 
substance. 

The  Cellular  Coat  of  the  small  intestine,  also  called  the  ner- 
vous, like  that  of  the  stomach,  is  only  a  lamina  of  condensed 
cellular  substance,  which  serves  as  a  medium  of  connexion  be- 
tween the  muscular  and  the  mucous  coat;  and  also  conducts  to 
the  latter  the  blood  vessels,  nerves,  and  lacteals. 

The  Mucous  Coat  is  the  most  internal,  and  when  it  has  been 
cleaned  by  maceration,  exhibits  an  opaque  pearly  colour.  It  is 
remarkable  for  having  its  extent  very  considerably  augmented 
beyond  that  of  the  other  coats;  by  being  thrown  into  a  great 
number  of  permanent  folds,  or  duplicatures,  which  lie  one  upon 
another  successively,  like  the  shingles  upon  the  roof  of  a  house. 
These  duplicatures  are  the  Valvulae  Conniventes,  and  are  for 
the  most  part  about  three  lines  in  breadth.  They  are  either 
placed  in  the  direction  of  the  circumference  of  the  intestine,  or 
are  very  slightly  oblique;  generally  they  go  all  around,  but 
some  of  them  are  segments  of  circles,  and  by  being  arranged 
successively,  their  ends  pass  one  another,  or  are  connected  by 
slight  elevations.  They  are  more  numerous  and  broad  in  the 
upper  than  in  the  lower  half  of  the  intestinum  tenue,  and  are 
evidently  intended  to  retard  the  progress  downwards  of  alimen- 
tary matter,  and  to  increase  the  surface  for  absorption  and  for 
exhalation. 

The  mucous  membrane,  on  the  side  which  it  presents  to  the 
cavity  of  the  intestine,  is  furnished  with  a  great  number  of  de- 
licate cylindrical  projections,  resembling  the  down  on  the  skin 
of  an  unripe  peach,  and  called  Villi,  from  whence  the  term  vil- 
lous  has  also  been  applied  to  this  coat.  These  villi  are  to  be 
found  in  abundance  every  where;  but  in  the  upper  half  of  the 
intestinum  tenue  they  are  so  numerous  as  to  stud  its  whole  sur- 
face, and  to  be  in  contact  with  each  other.  They  are  from  one- 
fourth  of,  to  a  line  in  length;  and  some  of  them,  when  examined 
with  a  microscope,  appear  flattened  and  fungiform.  According 
to  the  estimate  of  Meckel,*  where  they  are  thickest,  every 
square  inch  of  intestine  furnishes  about  four  thousand  of  them, 
and  by  extending  this  computation,  with  a  proper  allowance  for 

*  Manuel  D'Anat. 

VOL.  II.-5 


30  ORGANS  OF  DIGESTION. 

diminished  numbers  below,  their  aggregate  amount  is  about  one 
million. 

Each  Villus  is  composed  of  an  artery,  a  vein,  and  a  lympha- 
tic; all  united  by  cellular  substance.  From  the  extreme  vascu- 
larity  of  the  mucous  membrane,  the  blood  vessels  readily  re- 
ceive a  fine  injection  and  thereby  become  evident,  forming  a 
very  delicate  vascular  net-work  in  each  of  the  villi.  It  is  ascer- 
tained that  the  lymphatic  opens  on  its  surface,  but  whether  by 
one  or  more  orifices  is  yet  unsettled.  According  to  the  cele- 
brated Lieberkuhn,  there  is  commonly  but  one  orifice  at  the  end 
of  each  villus,  and  very  rarely  two:  this  assertion  he  considered 
himself  as  having  established  by  passing  a  current  of  air  through 
the  villus  till  it  was  dried,  and  then  slitting  it  open.  Hewson, 
Cruikshank,  and  W.  Hunter,  on  the  contrary,  are  said  to  have 
found  many  more,  amounting  even  to  twenty,  on  such  villi  as 
were  gorged  with  chyle.  The  subject  has  been  fruitful  with 
controversy  to  anatomists,  and  ranks  many  distinguished  cham- 
pions on  each  side;  but  as  from  the  minuteness  of  the  parts  un- 
der discussion  and  the  consequent  necessity  of  microscopical 
observations,  it  is  exposed  to  much  fallacy  and  illusion;  it  can- 
not be  satisfactorily  settled,  though  the  general  analogies  of 
papillary  structure  are  in  favour  of  the  latter  authorities.  The 
more  important  fact,  however,  is  ascertained  by  the  admission 
of  all,  that  there  is  a  branch  of  the  lymphatic  system  in  every 
villus;  which  has,  for  its  function,  the  absorption  of  chyle  from 
the  cavity  of  the  intestine. 

An  abundance  of  Mucous  Glands  is  found  deposited  in  the 
cellular  coat  of  the  small  intestine,  between  the  muscular  and 
the  villous;  the  ducts  of  which  open  upon  the  internal  surface  of 
the  latter,  in  the  interstices  of  the  villi,  and  from'their  smallness 
require  the  intestine  to  be  floated  in  water,  and  examined  with 
a  magnifying  glass,  before  they  can  be  recognised.  In  order 
to  see  the  glands  themselves,  the  intestine  must  be  cleaned  by 
soaking  it  in  water;  it  is  then  to  be  slit  open  longitudinally,  and 
held  between  the  eye  and  the  light,  in  which  case  the  glands 
appear  like  little  points  or  spots  in  the  thickness  of  the  intestine. 
They  are  more  abundant  in  the  beginning  of  the  latter,  decrease 
about  its  middle,  and  increase  again  towards  its  termination. 


INTESTINAL  CANAL.  31 

Their  structure  is  very  simple,  as  they  consist  in  a  congeries  of 
blood  vessels,  terminating  in  short  canals  secreting  mucus.* 

Some  of  these  glands  are  microscopical,  and  are  called  cryptae; 
others  are  to  be  found  from  that  size  to  a  line  in  diameter,  and 
flattened.  They  are  either  alone  or  in  clusters.  The  former 
( Glandulce  Solitarice,  Brunneri)  are  found  principally  about  the 
duodenum  and  the  neighbouring  portion  of  the  small  intestine. 
The  latter  ( Glandule  Agminatce,  Peyeri)  exist  principally  in  the 
lower  part  of  the  small  intestine,  and  are  collected  into  clusters 
varying  from  a  few  lines  to  three  or  four  inches  in  length,  but 
seldom  more  than  from  eight  to  twelve  lines  broad.  They  are 
for  the  most  part  in  elliptical  patches,  which  in  a  healthy  state 
may  be  recognised  rather  by  a  slight  discoloration,  than  by  the 
more  ordinary  means,  and  are  generally  situated  some  distance 
from  the  mesentery.  There  are  about  thirty  of  these  clusters, 
of  all  sizes,  in  the  ileum,  and  they  are  placed  nearer  and  nearer  to 
one  another,  in  approaching  the  ileo-colic  junction.  All  of  these 
muciparous  glands  are  too  much  flattened  to  project  sensibly  into 
the  cavity  of  the  intestine,  and  when  they  do,  there  is  reason  to 
believe  that  they  are  in  a  diseased  state,  at  least  in  the  adult:  for 
the  most  part,  in  children,  the  glands  of  Brunner  may  be  seen  in 
the  whole  length  of  the  small  intestine. 

The  mucous  coat  of  the  small  intestine  is  extremely  vascular. 

The  Small  Intestine,  though  an  uninterrupted  tube  from  one 
end  to  the  other,  is  divided  by  anatomists  into  Duodenum,  Jeju- 
num, and  Ileum.  There  is  some  reason  for  the  first  name,  but 
the  two  latter  may  be  very  conveniently  blended,  as  has  been 
done  by  some,  under  the  term  Mesenteric  Portion  of  the  intes- 
tinal canal. 

The  Duodenum,  named  from  its  being  about  twelve  inches,  or 
twelve  fingers%'  breadth  in  length,  is  nearest  to  the  stomach;  or, 
in  other  words,  is  the  commencement  of  the  canal.  It  is  larger 
than  either  of  the  others,  and  is,  moreover,  susceptible  of  great 
dilatation,  whence  it  has  also  been  called  Ventriculus  Suceentu- 

*  Soemmering,  de  Corp.  Hum.  Fabrica. 


32  ORGANS  OF  DIGESTION. 

riatus.  Its  direction  is  much  varied:  beginning  at  the  pylorus, 
it  first  of  all  passes  upwards  and  to  the  right  side,  till  it  reaches 
the  neck  of  the  gall-bladder;  it  then  turns  downwards,  so  as  to 
form  a  right  angle  with  itself,  and  descends  in  front  of  the  right 
kidney  to  the  third  lumbar  vertebra,  being  there  placed  behind 
the  superior  lamina  of  the  transverse  mesocolon.  It  then  forms 
a  round  elbow,  crosses  the  spine  obliquely,  under  the  junction  of 
the  mesentery  and  mesocolon,  in  ascending  from  right  to  left; 
and  making  its  appearance  to  the  left  of  the  second  lumbar  ver- 
tebra, is  there  continued  into  the  mesenteric  portion  of  intestine. 

The  beginning  of  the  duodenum  is  moveable,  and  has  a  pe- 
ritoneal coat  continued  from  the  lesser  omentum;  the  descend- 
ing and  the  transverse  portions  have  no  proper  peritoneal  coat, 
but  are  only  loosely  fixed  between  the  laminae  of  the  mesocolon ; 
the  termination  is  both  moveable  and  has  a  peritoneal  covering, 
from  being  at  the  commencement  of  the  mesentery. 

From  the  course  assigned  to  the  duodenum,  it  is  evident  that 
it  forms  the  segment  of  a  circle,  the  concavity  of  which  looks  to 
the  left  side.  This  concavity  is  occupied  by  the  head  of  the 
pancreas.  The  transverse  portion  crosses  the  spine  below  the 
latter,  and  is  separated  from  it  by  the  superior  mesenteric  artery 
and  by  the  vena  portarum:  behind  it  are  the  crura  of  the  dia- 
phragm, the  ascending  cava,  and  the  aorta. 

The  organization  of  the  duodenum  is  the  same  with  that  of 
other  portions  of  the  intestinum  tenue.  Its  peculiarities  consist 
only  in  a  partial  deficiency  of  peritoneal  coat,  and  in  its  aug- 
mented size.  Its  internal  or  mucous  coat  is  very  much  tinged 
with  bile,  abounds  in  valvulae  conniventes,  and  about  four  inches 
from  the  pylorus  is  marked  by  a  small  tubercle  or  elevation,  in- 
dicative of  the  orifice  of  the  biliary  and  of  the  pancreatic  ducts. 
The  Glands  of  Brunner  are  very  conspicuous  in  this  intestine, 
and  are  so  numerous  near  .the  pyloric  orifice,  as  to  form  with 
some  a  perfect  layer. 

The  Jejunum  and  Ileum  form  the  remaining  length  of  the 
small  intestine,  and  have  no  external  marks  of  difference  from 
each  other.  They  are  strung  along  the  mesentery,  and,  in  con- 
sequence of  their  great  length,  are  thrown  into  folds  ort  convolu- 
tions, which  give  to  them  a  complicated  appearance.  There  is, 
however,  no  difficulty  in  tracing  them  regularly  from  one  end  to 


INTESTINAL  CANAL.  33 

the  other.  They  occupy  the  umbilical,  the  hypogastric,  and  a 
part  of  the  iliac  regions,  and  are  surrounded  by  the  circuit  of 
the  colon.  The  upper  two-fifths  is  the  jejunum,  and  the  lower 
three-fifths,  the  ileum.  This  distinction,  originally  introduced  by 
Galen,*  from  a  supposition  that  the  jejunum  was  more  fre- 
quently found  empty  than  any  other  intestine,  has  no  rigid  ana- 
tomical support.  The  only  difference  between  the  two  is,  that 
the  valvulae  conniventes,  abundant  in  the  whole  length  of  the  je- 
junum, become  less  so  at  the  upper  part  of  the  ileum,  and  finally 
disappear  entirely  towards  its  lower  extremity.  The  distinction 
has,  therefore,  been  rejected  by  the  most  approved  modern  au- 
thorities, such  as  Haller,  Scemmering,  Meckel,  and  so  on. 

It  sometimes  happens,  that  the  intestinum  tenue  has  one  or 
more  blind  pouches  appended  to  its  sides  and  opening  into  its 
cavity. 

The  small  intestine  is  supplied  with  blood  from  the  superior 
mesenteric  artery ;  its  nerves  come  from  the  sympathetic. 

The  Mesentery  (Mesenterium)  is  a  process  of  peritoneum 
which  serves,  as  mentioned,  to  connect  the  intestinurn  tenue  to 
the  posterior  parietes  of  the  abdomen,  and  extends  its  connex- 
ions from  the  left  side  of  the  second  lumbar  vertebra  to  the  right 
iliac  fossa.  This  attachment,  called  the  root,  is  about  six  inches 
in  length ;  whereas  its  lower  circumference,  which  encloses  the 
small  intestine  by  giving  it  a  peritoneal  coat,  is,  of  course,  the 
whole  length  of  the  bowel,  (duodenum  excepted,)  and,  conse- 
quently, from  twenty-three  to  twenty-seven  feet  in  length.  This 
expansion  becomes  intelligible  the  moment  that  the  arrangement 
of  the  part  is  inspected,  and  is  somewhat  after  the  manner  of  a 
ruffle,  except  that  it  is  not  puckered  at  the  root. 

The  two  laminae  of  peritoneum  which  form  the  mesentery, 
contain  between  them  the  superior  mesenteric  artery,  and  the 
corresponding  portion  of  the  superior  mesenteric  vein ;  an  abun- 
dance of  lymphatic  or  lacteal  glands  and  vessels ;  ramifications 
from  the  solar  plexus  of  the  sympathetic  nerve ;  and  a  considera- 
ble quantity  of  cellular  and  of  adipose  tissue.  The  superior  la- 
mina is  continued  directly  into  the  mesocolon,  and  at  the  place, 
of  junction  the  transverse  part  of  the  duodenum  is  very  percep- 
tible beneath.  The  lower  lamina  descends  along  the  posterior 

*  Portal,  Anat.  Med. 


34  ORGANS  OF  DIGESTION. 

parietes  of  the  abdomen,  concealing  the  large  blood  vessels 
there  and  the  ureters. 


Of  the  Large  Intestine. 

The  Large  Intestine  (Intestinum  Crassum)  receives  the  effete 
matter  from  the  small,  and  is  supposed  also  to  have  some  pecu- 
liar secretion  of  fcecal  matter  from  the  internal  surface.  It  ex- 
ceeds much  in.  its  diameter  the  small  intestine,  and  differs  also 
from  it  in  not  being  by  any  means  so  regularly  cylindrical.  It 
commences  at  the  inferior  end  of  the  small  intestine,  and  termi- 
nates at  the  anus,  describing  in  this  course,  as  mentioned,  a  cir- 
cle which  surrounds  two-thirds  of  the  abdomen,  and  embraces 
the  intestinum  tenue.  Like  the  latter,  though  only  a  continuous 
tube,  it  is  divided  into  three  parts ;  the  commencement  of  it, 
which  is  below  the  insertion  of  the-ileum,  and  about  two  inches 
in  length,  is  the  Coecum,  or  Caput  Coli;  the  remaining  portion, 
which  occupies  almost  its  whole  length,  is  called  the  Colon, 
until  it  reaches  the  pelvis,  when  the  name  is  converted  into 
Rectum. 

The  Mesocolon  is  a  reflection  or  duplication  of  peritoneum, 
that  fixes  the  large  intestine  to  the  posterior  parietes  of  the  abdo- 
men. This  duplicature  is  not  of  a  breadth  so  uniform  as  the 
mesentery,  but  allows  to  the  middle  of  the  large  intestine  very 
considerable  motion,  up  and  down,  according  to  the  distention 
of  the  stomach,  while  the  lateral  portions  are  very  much  confined. 
For  example,  in  the  right  iliac  fossa  the  mesocolon  is  so  short 
that  the  posterior  surface  of  the  gut  is  in  contact  with  the  iliac 
fascia,  and  adheres  to  it  by  loose  cellular  substance ;  in  the  right 
and  left  lumbar  regions  the  bowel  is  immoveably  fixed  in  front 
of  the  kidneys,  but  in  the  space  between  these  two  points,  that  is 
to  say,  where  the  bowel  traverses  the  hypochondriac  and  the 
epigastric  or  umbilical  regions,  the  peritoneal  attachment,  here 
called,  from  its  situation,  the  transverse  mesocolon,  is  so  long 
and  loose  that  it  forms  a  complete  and  moveable  septum  between 
the  small  intestine  and  the  stomach.  In  the  left  iliac  region, 
again,  the  large  intestine,  after  having  been  bound  down  to  the 
left  lumbar,  is  suddenly  loosened  by  an  increased  breadth  of  the 


INTESTINAL  CANAL.  35 

mesocolon,  which  permits  it  to  form  a  large  convolution,  called 
ifs  sigmoid  flexure.  The  mesocolon  is  then  continued  into  the 
pelvis  in  front  of  the  sacrum,  first  of  all  a  little  to  the  left  of  the 
middle  line  of  the  latter,  and,  as  it  descends,  it  gets  directly  in 
front  of  the  middle  line.  The  portion  of  it  in  the  pelvis  is  called 
mesorectum,  after  the  gut  which  it  serves  to  attach. 

The  composition  of  the  mesocolon  is  precisely  the  same  with 
that  of  the  mesentery,  though  it  be  not  so  thick:  it,  therefore, 
consists  in  two  laminae  of  peritoneum,  which  contain  between 
them  some  adipose  and  cellular  matter,  along  with  the  arteries, 
the  veins,  the  nerves,  and  the  lymphatic  vessels  and  glands  be- 
longing to  the  large  intestine. 

When  the  large  intestine  is  inflated,  it  is  rendered  very  ob- 
vious that  it  decreases  in  size  from  its  commencement  to  the 
lower  part  of  the  sigmoid  flexure,  it  then  increases  again  in  size 
just  above  the  anus.  Its  surface  is  arranged  into  three  series  or 
longitudinal  rows  of  projections,  separated  by  transverse  depres- 
sions, the  whole  corresponding  with  an  internal  cellular  arrange- 
ment, by  the  latter  surface  being  the  reverse  of  the  former. 

Its  coats,  like  the  small  intestine,  are  four  in  number ;  the  pe- 
ritoneal, the  muscular,  the  cellular,  and  the  mucous. 

The  Peritoneal  Coat  prevails  in  its  whole  extent,  with  the 
exception  of  the  lower  part  of  the  rectum:  on  the  ascending  and 
the  descending  portions  of  the  colon,  however,  where  the  latter 
comes  in  contact  with  the  parietes  of  the  abdomen,  the  perito- 
neum does  not  invest  it  entirely ;  but  the  transverse  portion  or 
the  arch,  as  it  is  called,  and  the  sigmoid  flexure,  are  completely 
surrounded. 

The  surface  of  this  intestine  is  studded  with  small  projections 
of  various  lengths,  called  Appendices  Epiploicae,  which  are  small 
duplicatures  of  peritoneum  containing  fat. 

The  Muscular  Coat  is  thin,  like  that  of  the  small  intestine,  and 
consists  in  two  orders  of  fibres,  the  longitudinal,  and  the  trans- 
verse or  circular. 

The  longitudinal  fibres  have  the  peculiarity  of  being  collected 
into  three  equidistant,  flattened  fasciculi  or  bands,  of  about  half 


36  ORGANS  OF  DIGESTION. 

an  inch  in  breadth,  which  begin  by  a  common  point  at  the  ex- 
tremity of  the  coecum,  and  extend  to  the  upper  end  of  the  rec- 
tum. One  of  them  is  along  the  line  of  junction  with  the  meso- 
colon,  another  anterior,  and  the  third  inferior.  These  fibres, 
being  shorter  than  the  other  coats  of  the  gut,  have  the  effect  of 
puckering  them  into  the  internal  cellular  condition  alluded  to; 
for,  when  they  are  cut  through,  the  intestine  is  much  elongated,- 
and  its  cells  disappear.  It  occasionally  happens  that  the  longi- 
tudinal fibres,  instead  of  being  confined  to  the  bands  alluded  to, 
exist  in  considerable  quantity  over  the  intermediate  spaces;  in 
this  case  the  cellular  arrangement  is  restricted,  and  in  some  in- 
stances entirely  dispensed  with ;  of  the  latter,  an  example  is  in 
the  Anatomical  Museum. 

The  circular  muscular  fibres  form  a  thin  semi-transparent  la- 
mina beneath  the  last,  and  do  not  present  any  peculiarity  of  in- 
terest. 

The  Cellular  Coat  is  a  condensed  thin  lamina  of  cellular  sub- 
stance, serving  to  connect  the  muscular  with  the  mucous  coat, 
and  to  conduct  the  blood  vessels  and  nerves  to  their  terminations 
on  the  latter. 

The  Mucous  Coat  lines  smoothly  the  internal  face  of  the  cel- 
lular, and  has  no  doublings  or  folds,  exclusively  in  it,  like  the 
valvulae  conniventes  of  the  small  intestine. *  -  The  transverse 
projections  which  it  makes  between  the  longitudinal  bands,  into 
the  cavity  of  the  gut,  and  which  separate  the  cells  of  the  large 
intestine  from  each  other,  are  not  mere  duplicatures  of  it  alone, 
but  are  also  constituted  by  the  other  coats. 

Near  its  commencement  this  coat  has  the  fungous  appearance ' 
of  the  stomach,  but  about  the  sigmoid  flexure  it  has  a  plane, 
smooth,  and,  to  a  degree,  a  polished  surface.  It  has  but  few 
villi,  such  as  exist  in  the  small  intestine;  indeed,  by  some  anato- 
mists it  is  denied  that  it  has  any.  Its  muciparous  glands  and 
follicles  are  numerous,  and  the  former,  when  somewhat  enlarged, 
project;  they  are  unusually  conspicuous  about  the  sigmoid 
flexure,  and  in  the  rectum.  Its  lacteals  are  not  abundant 

*  This  may  be  considered  as  the  general  rule:  if  it  be  examined,  however,, 
in  its  whole  length,  here  and  there  narrow  ones  may  be  found. 


VTESTINAL    CANAL.  37 

The  mucous  coat  of  the  large  intestine  is  very  vascular,  but 
not  so  much  so  as  that. of  the  small  intestine. 

Each  division  of  the  large  intestine  has  some  peculiari- 
ties of  structure  and  connexion;  which  may  now  be  attend- 
ed to. 

The  Coecum,  or  Caput  Coli,  is  generally  from  an  inch  and  a 
half  to  two  inches  long,  has  a  rounded  termination  below  and 
somewhat  to  the  left,  from  which  proceeds  an  intestinal  pro- 
cess, the  Appendicula  Vermiformis.  The  latter  is  from  three 
to  four  inches  long,  is  cylindrical,  has  a  diameter  of  two  or  three 
lines,  and  consists  also  of  the  same  number  of  coats,  having  the 
same  structure  with  other  portions  of  the  intestinal  canal;  its 
base  is  the  point  from  which  the  three  longitudinal  bands  start. 
It  is  attached  by  a  narrow  duplicature  of  peritoneum,  a  process 
of  the  mesentery,  which  permits  it  to  float  loosely  in  the  abdo- 
men. It  seldom  contains  faeces,  but  it  is  kept  distended  by 
flatus. 

The  coecum,  as  mentioned,  is  for  the  most  part  confined  to 
the  right  iliac  fossa,  but  we  very  frequently  see  it  with  a  length 
of  peritoneal  attachment  permitting  it  to  descend  for  a  short 
distance  into  the  pelvis. 

The  Ileo-colic  Valve  ( Valviila  Bauhini}  is  formed  at  the 
junction  of  the  ileum  with  the  caput  coli.  This  valve,  destined 
to  prevent  the  return  of  faecal  matter  from  the  large  into  the 
small  intestine,  consists  in  a  transverse  elliptical  opening,  or 
slit,  whose  lips  become  approximated  in  the  distentions  of  the 
colon.  The  ileum  runs  into  the  left  wall  of  the  large  intestine, 
and  continues  its  cellular  and  mucous  coats  into  the  correspond- 
ing coats  of  the  latter.  The  circular  muscular  fibres  of  the  large 
intestine  separate  to  a  certain  degree  to  permit  this  introduction, 
but  their  farther  separation  is  restrained  at  each  commissure  or 
corner  of  the  lips,  by  a  blending  of  the  structure,  aided  by  a 
few  ligamentous  fibres,  designated  as  the  retinacula  of  Bauhin 
or  of  Morgagni;  which,  however,  are  frequently  not  very  dis- 
tinct. This  separation  is  also  restrained  by  the  two  longitudinal 
bands  between  which  they  are  inserted,  one  of  which  is  at  the 
posterior  commissure  and  the  other  only  a  short  distance  off 
VOL.  II.— 6 


38  ORGANS  OF  DIGESTION. 

from  the  anterior.  The  lips  themselves,  formed  principally  by 
the  mucous  membrane,  approach  one  another  after  the  man- 
ner of  the  ship  dock  or  canal  gate;  the  superior  is  somewhat 
broader  than  the  inferior.  Their  power,  as  well  as  their 
existence  depend  entirely  on  the  tension  which  is  kept  up  by 
the  natural  connexions  of  the  parts;  for  a  very  slight  dissection 
causes  them  to  become  almost  effaced,  and  instead  of  forming 
an  elliptical  transverse  opening,  to  be  converted  into  a  round 
patulous  one. 
• 

The  Colon,  properly  speaking,  has  some  regional  distinctions 
which  are  serviceable  to  accurate  description.  The  right  lumbar 
colon,  which  is  bordered  in  front  by  the  small  intestine,  and 
behind,  by  the  right  kidney,  extends  from  the  ileo-colic  valve, 
to  the  margin  of  the  false  ribs  of  the  corresponding  side.  The 
transverse  colon,  bordered  above  by  the  stomach,  and  below  by 
the  small  intestine,  goes  from  one  hypochondriac  region  to  the 
other.  It  is  generally  found  more  distended  than  the  other 
portions.  The  left  lumbar  colon  descends  from  the  hypo- 
chondriac region  of  the  left  side  to  the  sigmoid  flexure,  being 
bordered  behind  by  the  left  kidney,  and  in  front  by  the  small 
intestine.  The  sigmoid  flexure,  placed  in  the  left  iliac  fossa, 
forms  a  convolution,  but  is  very  indifferently  described  by  the 
term  applied  to  it.  It  is  occasionally  very  long  and  loose,  and 
terminates  at  the  left  sacro-iliac  symphysis.  It  is  not  unfre- 
quently  found  destitute  of  the  partitions  which  prevail  in  other 
parts. 

The  Rectum  begins  at  the  left  sacro-iliac  symphysis,  and 
passes  obliquely  downwards  to  the  centre  of  the  sacrum,  thence 
in  front  of  the  middle  line  of  the  sacrum,  and  of  the  coccyx,  to 
terminate  at  the  point  of  the  latter.  It  is  not  regularly  cylin- 
drical, but,  just  above  the  anus,  is  dilated  into  a  wride  pouch, 
flattened  from  before  backwards  by  the  pressure  of  the  bladder, 
and  very  distinguishable  upon  the  introduction  of  the  finger,  for 
it  is  but  seldom  in  a  contracted  state.  It,  of  course,  has  a  flexure 
by  adapting  itself  to  the  concavity  of  the  sacrum,  and  is  bound- 
ed in  front  by  the  bladder,  the  prostate  gland  and  the  vesiculae 
seminales  of  the  male,  and  by  the  vagina  and  the  uterus  of  the 
female. 


INTESTINAL  CANAL.  39 

The  peritoneum  covers  only  the  superior  two-thirds  of  the 
rectum,  and  attaches  it  by  the  short  duplicature,  called  the  me- 
sorectum,  to  the  front  of  the  sacrum.  A  small  pouch,  passing 
down  between  the  vesiculae  seminales  almost  to  the  base  of  the 
prostate,  is  formed,  as  mentioned  previously,  by  the  peritoneum 
in  its  course  from  the  rectum  to  the  bladder. 

The  muscular  coat  of  the  rectum  has  a  thickness  and  redness 
surpassing  much  that  of  any  other  intestine,  and  is  divided  very 
clearly  into  two  laminae,  the  external  of  which  consists  in  lon- 
gitudinal and  the  internal  in  circular  fibres.  The  external  forms 
in  itself  a  complete  coat  continuous  with  the  longitudinal  bands 
of  the  colon,  but  is  much  increased  by  additional  fibres.  The 
circular  fibres  also  form  a  complete  coat,  and,  just  below  the 
pouch  of  the  rectum,  are  multiplied  so  much  for  eight  or  ten 
lines  as  to  be  a  perfect  internal  sphincter  muscle,  bearing  a 
strong  analogy  with  the  pyloric  muscle  of  the  stomach.  At  the 
anus,  an  arrangement  of  the  muscular  coat  prevails,  which,  as 
far  as  I  know,  has  not  been  heretofore  attended  to  by  anato- 
mists. The  longitudinal  fibres,  having  got  to  the  lower  margin 
of  the  internal  sphincter,  turn  under  this  margin  between  it  and 
the  external  sphincter,  and  then  ascend  upwards  for  an  inch  or 
two  in  contact  with  the  mucous  coat,  into  which  they  are  final- 
ly inserted  by  fasciculi  which  form  the  base  of  the  columns  of 
the  rectum;  many  of  the  fibres,  however,  terminate  also  between 
the  fasciculi  of  the  circular  fibres.  This  connexion  roust  have 
obviously  much  influence  in  the  protrusions  of  the  mucous  coat, 
which  sometimes  take  place. 

The  mucous  coat  of  the  rectum  is  thick,  red,  and  fungous, 
and  abounds  in  mucous  lacunas  and  glands.  It  is  smoothly  laid 
above,  but  below  it  is  thrown  into  superficial  longitudinal  folds 
called  columns.  At  the  lower  ends  of  the  wrinkles,  between 
the  columns,  are  small  pouches  of  from  two  to  four  lines  in 
depth,  the  orifices  of  which  point  upwards;  they  are  occasional- 
ly the  seat  of  disease,  and  produce,  when  enlarged,  a  painful 
itching.  An  original  observation  of  Dr.  Physick,  on  the  nature 
of  this  affection,  and  the  remedy  for  which  consists  in  slitting 
them  open  or  removing  them,  induced  me  to  look  for  the  ordi- 
nary natural  structure,  which  I  have  found  to  be  as  now  de- 


40  ORGANS  OP  DIGESTION. 

scribed.*  The  wrinkling  of  the  anus  is  from  the  influence  of 
the  external  sphincter  ani  muscle.  In  some  subjects,  large 
cells  are  formed  in  the  cavity  of  the  rectum  by  transverse 
doublings  of  the  mucous  coat  only,  resembling  the  valvulae  con- 
niventes  of  the  small  intestine;  this,  however,  is  not  the  most 
frequent  arrangement,  though  deserving  of  notice. 

The  large  intestine  is  supplied  with  blood  from  a  part  of  the 
superior  mesenteric,  from  the  whole  of  the  inferior  mesenteric, 
and  from  the  internal  pudic  artery.  Its  veins  empty  into  the 
vena  portarum.  Its  nerves  are  derived  from  the  solar  and  the 
hypogastric  plexus  of  the  sympathetic. 

SECT.  III. ON  THE  MINUTE  ANATOMY  OF  THE  MUCOUS  COAT 

OF  THE  ALIMENTARY  CANAL. 

In  the  preceding  account  of  the  mucous  coat  of  the  stomach 
and  bowels,  I  have  admitted  the  most  generally  received  opi- 
nions, as  it  is  in  every  way  proper  for  medical  men  to  be  aware 
of  them.  Having  been,  however,  much  occupied,  a  short  time 
ago,  in  ascertaining  the  pathology  of  Asiatic  cholera  by  dissec- 
tions, the  observations  which  I  then  made  upon  the  healthy 
and  diseased  structure  have  induced  me  to  modify  very  much 
my  former  views^  as  will  be  seen  in  the  following  pages,  f 

The  mucous  coat  of  the  alimentary  canal,  in  a  healthy  state, 
and  successfully  injected,  appears  to  consist  almost  entirely  of 
a  cribriform  intertexture  of  veins;  these  veins  being  commonly 
empty  at  death  present  themselves  as  a  soft  spongy  structure, 
which  gives  rise  to  the  ordinary  description  of  its  sensible  con- 
dition as  a  velvety  layer.  The  most  minute  injection  of  the  ar- 
teries scarcely  makes  itself  visible  among  these  veins  when  they 
are  properly  injected,  a  straggling  branch  only  here  and  there 
exhibiting  itself.  The  arborescence  of  the  arteries  is  confined 
to  the  level  beneath  the  venous  intertexture,  and  is  there  deve- 

*  See  an  interesting  paper  on  Fistula  in  ano,  by  M.  Ribes,  in  Mem.  de  la  So- 
ciete"  D'Emulation,  vol.  9,   1826;  where  the  influence  of  this  structure  is  al- 
luded to. — It  appears  that  Glisson  and  Ruysch  first  described  them  as  valves. 
Also,  an  elaborate  and  excellent  article  by  Dr.  Reynell  Coates,  in  the  Cyclopaedia 
of  Pract.  Med.  and  Surgery,  Philada.  1835,  under  the  term  anus. 

-  Amer.  Journ.  Med.  Sciences  for  1835. 


ANATOMY  OF  THE  MUCOUS  COAT.  41 

loped  to  an  extreme  degree  of  minuteness,  being  intermixed 
with  corresponding  venous  ramuscles,  generally  larger  and  more 
numerous  than  the  arteries  themselves.  The  fine  venous  trunks 
of  this  deeper  layer  have  their  originating  extremities  bent  ver- 
tically towards  the  cavity  of  the  gut,  and  by  that  means  receive 
the  blood  of  the  first  venous  intertexture  or  layer,  as  the  petrous 
sinuses  join  the  cavernous,  or  the  veins  of  the  penis  arise  from 
its  spongy  structure.  The  meshes  of  the  first  venous  intertex- 
ture are  exceedingly  minute,  and  vary  in  a  characteristic  man- 
ner in  the  stomach,  small  intestines  and  colon.  This  intertex- 
ture is  very  different  in  its  looks  from  a  common  vascular  anas- 
tomosis, and  produces  in  the  colon  an  appearance  resembling 
a  plate  of  metal  pierced  with  round  holes  closely  bordering  upon 
each  other;  these  holes  constitute,  in  fact,  follicles  or  gaping  ori- 
fices, the  edges  of  which  are  rounded  off,  and  their  depth  is  that 
of  the  thickness  of  the  venous  anastomosis  being  bounded  be- 
low by  the  arterial  venous  layer,  and  by  the  cellular  coat  of  the 
part  Nothing  short  of  an  entirely  successful  injection  will 
exhibit  this  venous  anastomosis  as  described;  and  it  may  be  seen 
either  by  injecting  a  vein  or  an  artery,  provided  the  injection 
passes  from  the  artery  into  the  veins,  but  the  latter  process  is 
the  least  desirable,  because  we  lose  the  benefit  of  a  distinction 
of  colour  between  the  two  sets  of  vessels. 

Ordinary  modes  of  examination  give  no  evidence  of  the  exis- 
tence in  the  alimentary  canal,  from  the  cardiac  orifice  of  the 
stomach  to  near  the  anus,  of  an  epidermis;  on  the  contrary,  they 
rather  lead  to  a  belief  of  its  being  absent,  in  consequence  of  the 
softness,  tenuity,  and  transparency  of  the  mucous  membrane; 
but  that  it  is  really  present,  may  be  proved  by  the  following 
process: — Tear  off  the  peritoneal  coat — invert  the  part  and  in- 
flate it  to  an  emphysematous  condition;  the  epidermis  will  then 
be  raised  as  a  very  thin  pellicle,  and  may  be  dried  in  that  state; 
but  as  this  pellicle  retains  the  air,  we  hence  infer  that  it  lines 
the  follicles,  and  is  uninterrupted  by  any  perforations.  This 
epidermis,  if  the  part  be  previously  Injected  perfectly,  shows 
dots  of  injecting  matter,  but  no  arborescence  if  it  be  inflated  up 
from  the  veins.  In  so  doing  the  villi  disappear,  are  in  fact  un- 
folded. 

The  villi  cannot  be  seen  to  any  advantage  except  they  be 


42  ORGANS    OP  DIGESTION. 

erected  by  an  injection,  in  which  case  those  of  the  upper  part 
of  the  small  intestines  are  found  to  run  into  each  other  very 
much  like  the  convolutions  of  the  cerebrum,  and  to  press  upon 
each  other's  sides  in  the  same  way.  Some  of  them,  however, 
are  merely  semi-oval  plates,  the  transverse  diameter  of  which 
exceeds  the  length.  At  the  lower  end  of  the  small  intestine 
they  become  simply  conical  projections,  somewhat  curved, 
with  the  edges  bent  in,  and  they  retain  this  mechanism  until 
they  entirely  disappear  near  the  ileo-coli6  valve.  In  the  whole 
length  of  intestine  there  is,  however,  every  variety  of  shape, 
from  oblong  curved  and  serpentine  ridges,  to  the  flattened  cone 
standing  on  its  base;  the  first  condition  changing  gradually  to 
the  last  in  the  descent  of  the  bowel.  Conformably  to  this  de- 
finition of  villi,  none  exist  either  in  the  stomach  or  colon,  for 
there  we  have  only  the  venous  mesh.  The  villi  of  the  jejunum 
are  about  the  thirtieth  of  an  inch  high,  and  those  of  the  ileum 
about  one-sixtieth. 

The  superficial  venous  layer  has  great  regularity  in  the  ileum, 
and  the  conical  villi  stand  out  beautifully  from  its  partitions,  or 
in  equivalent  language,  from  the  divisions  of  the  follicles.  In 
the  upper  part  of  the  small  intestine  the  follicles  are  in  equal 
number  to  what  they  are  in  the  ileum;  the  regularity  of  their 
arrangement  being  interrupted  by  the  long  serpentine  and  oval 
villi;  but  invariably  the  same  venous  intertexture  exists  and 
forms  in  both  the  chief  bulk  of  the  villi,  by  passing  into  them. 

In  the  stomach  the  follicles  vary  much  in  size,  and  there  is 
an  arrangement  whereby  many  of  the  smaller  ones  are  seen  to 
open  into  the  larger:  on  an  average  about  two  hundred  and 
twenty-five  are  found  upon  every  eighth  of  an  inch  square, 
which  would  give  of  course  to  an  inch  square  sixty-four  times 
that  amount,  or  fourteen  thousand  four  hundred  follicles;  and 
conceding  the  whole  stomach  to  present  an  area  of  ninety 
inches,  which  is  probably  below  the  mark  when  this  organ  is 
moderately  distended,  as  exhibited  in  the  preparation  upon  which 
this  calculation  is  founded,  the  entire  number  of  follicles  is  one 
million  tioo  hundred  and  ninety-six  thousand. 

The  great  uniformity  of  size  of  these  follicles  in  the  colon, 
and  its  even  surface,  enable  us  to  count  them  with  more  cer- 
tainty, and  they  appear  to  exist  at  the  beginning  of  this  gut  at 


ANATOMY  OF  THE  MUCOUS  COAT.  43 

the  rate  of  about  four  hundred  for  every  eighth  of  an  inch 
square,  but  in  the  sigmoid  flexure  at  the  rate  of  about  two  hun- 
dred to  the  same  area;  they  become,  in  fact,  both  smaller  and 
less  numerous  in  descending  towards  the  anus.  Admitting  the 
entire  area  of  the  colon  to  be  five  hundred  inches,  and  nineteen 
thousand  two  hundred  of  these  follicles,  on  an  average,  to  exist 
on  every  inch  square,  the  aggregate  number  will  be  nine  mil- 
lions six  hundred  and  twenty  thousand. 

Again,  estimating  the  whole  area  of  the  mucous  coat  of  the 
small  intestines  at  fourteen  hundred  and  forty  inches,  and  al- 
lowing for  interruptions  occasioned  by  villi,  about  twenty-five 
thousand  follicles  are  found  upon  every  square  inch,  and  the 
two  numbers  multiplied,  produce  thirty-six  millions. 

The  entire  number  of  follicles  in  the  whole  alimentary  canal 
is,  by  the  preceding  estimates,  forty-six  millions  nine  hundred 
thousand,  and  upwards.  I  am  very  far  from  pretending  to 
have  counted  them  all,  but  have  made  an  approximation  to  the 
actual  number  by  observing  sections  of  different  portions  of  the 
same  subject,  and  verifying  the  observations  upon  other  subjects. 
The  external  surface  of  the  cutis  vera  presents,  as  it  were,  in 
outline  the  same  arrangement;  the  venous  reticular  intertexture 
appearing  broader,  not  quite  so  perfect,  and  more  shallow,  and 
forming  the  papillae;  tjutas  additional  experiments  are  wanting, 
it  may  be  passed  over  with  this  transient  notice;  perhaps, 
indeed,  a  more  skilful  hand  in  adopting  the  hint  may  perfect 
the  details. 

In  the  stomach,  the  largest  of  these  follicles  is  about  ^\\\  of 
an  inch  in  diameter,  and  the  smallest  about  TJo-th.  In  the  co- 
lon the  largest  is  about  ^Jyth  of  an  inch  in  diameter,  and  the 
smallest  about  -^th.  In  the  small  intestines  their  size  varies 
in  about  the  same  ratio  as  in  the  colon,  but  they  are  much  more 
irregular  in  shape,  being  scattered  more  in  groups  in  conse- 
quence of  the  villi  intervening:  some  of  them  penetrate  oblique- 
ly towards  the  foundations  of  the  villi;  hence,  when  examined 
from  the  exterior,  their  distribution  is  more  regular,  and  they 
are  seen  lodged  in  the  cellular  coat  of  the  gut. 

I  have  endeavoured  to  keep  the  estimate  of  the  number  of 
follicles  below  what  other  calculators  would  make  it  upon  an 
observation  of  my  preparations,  and  a  fair  measurement  of  the 


44  ORGANS  OF  DIGESTION. 

area  of  the  alimentary  canal,- lest  the  number  may  seem  exces- 
sive and  incredible;  I  have  therefore  the  most  reasonable  as- 
surance of  being  within  bounds  on  that  point.  I  may  now  ask 
their  use;  is  it  to  secrete  or  absorb?  If  they  are  simply  se- 
cernents  of  mucus,  the  number,  one  would  think,  much  greater 
than  so  limited  a  secretion  requires — moreover,  why  is  it  that 
they  become  smaller  and  less  numerous  towards  the  lower  end 
of  the  large  intestine,  where  greater  lubrication  is  required  for 
hardened  faeces;  in  addition,  are  not  the  glands  of  Brunner,  (so- 
litarige,)  and  of  Peyer,  (agminatse,}  amply  sufficient  to  furnish 
the  required  mucus?  Again,  after  most  sedulous  observations 
upon  the  villi  of  all  kinds,  finely  erected  by  my  injections,  and 
placed  under  most  accurate,  simple,  and  compound  microscopes, 
J  find  invariably  a  polished  reflecting  surface,  uninterrupted  by 
foramina,  either  at  their  ends  or  sides,  while  many  of  these  fol- 
licles are  found  passing  obliquely  into  their  bases.  An  excel- 
lent Woollaston's  doublet,  which  makes  the  villi  of  the  ileum 
appear  an  inch  long,  exhibits  them  with  a  polished  translucent 
surface,  without  foramina,  except  where  a  villus  from  accident 
has  been  broken,  a  contingency  readily  recognised  by  one  in 
the  habit  of  viewing  them.  Finally,  if  the  lacteal  foramina  of 
Lieberkuhn  and  others,  do  exist  in  fact,  why  is  it  that  the 
raising  of  the  intestinal  epidermis  by  inflation  does  not  exhibit 
these  foramina  by  the  air  escaping  through  them,  but  on  the 
contrary,  admits  of  a  dried  preparation  in  that  state,  the  villi 
being  completely  effaced. 

In  these  and  other  microscopical  observations,  I  have  been 
much  assisted  by  my  young  friend,  Dr.  Paul  Beck  Goddard, 
who  has  acquired  an  accuracy  and  skill  in  such  matters  deserving 
of  confidence. 

Taking  into  consideration  these  several  objections  to  the  theo- 
ry of  the  follicles  being  secreting  orifices,  it  appears  to  me  that 
a  better  idea  of  their  use  is  called  for,  which  suggestion  is  sub- 
mitted to  the  profession,  with  the  hope  that  a  more  capable  per- 
son will  remove  the  difficulty  by  additional  confirmation  of  pre- 
ceding theories,  or  by  the  invention  of  a  new  one:  for  my  own 
part,  I  am  much  inclined  to  adopt  the  opinion  of  their  absorb- 
ing faculties.  It  is  generally  conceded  that  the  erection  and  pre- 
hension of  the  Fallopian  tube  is  produced  by  a  vascular  tur- 


ANATOMY  OF  THE  MUCOUS  COAT.  45 

gescence,  in  which  the  veins,  from  their  number,  must  execute 
an  important  part;  in  like  manner  as  these  follicles  are  formed 
in  the  midst  of  veins,  their  orifices  only  become  erect  and  pa- 
tulous  by  the  distention  of  those  veins,  and  cannot  be  seen, 
especially  in  the  small  intestine,  unless  an  injection  has  suc- 
ceeded fully;  but  the  erection  of  these  veins  during  digestion 
puts  the  follicles  in  a  similar  condition;  there  is  therefore  some 
ground  of  inference,  that  the  act  of  the  Fallopian  tube  in  con- 
veying a  germ,  and  of  a  follicle  in  conveying  into  the  thick- 
ness of  an  intestine  congenial  matter,  may  be  analogous. 

Notwithstanding  the  facility  with  which  I  can  detect  these 
follicles,  I  have  failed  entirely  under  various  means  of  exami- 
nation, in  finding  any  orifices  to  Peyer's  glands,  in  the  dried 
intestine;  they  appear  to  be  merely  small  lenticular  excavations 
in  its  substance,  and  wherever  a  cluster  of  them  exists,  it  dis- 
turbs the  arrangement  of  the  villi,  and  gives  to  them  a  scatter- 
ing unequal  distribution.  I  would  also  suggest  very  respecful- 
ly  to  anatomists  whether  our  knowledge  in  regard  to  them  is 
sufficiently  exact  to  render  farther  inquiry  useless?  for  my  own 
part  it  appears  that  this  subject  requires  some  additional  attention. 

The  above  view,  relative  to  the  structure  of  mucous  membrane, 
presents  at  least  a  degree  of  novelty,  by  determining,  with  some 
precision,  the  whole  number  of  the  G  astro -enteric  Follicles  of 
the  human  body,  and  how  they  are  in  every  instance  formed  by 
meshes  of  veins,  while  the  arteries  enter  only  inconsiderably  into 
their  composition,  to  an  amount  in  some  measure  comparable  to 
the  presence  of  the  arteries  in  other  erectile  tissues,  as  the  corpus 
spongiosum  and  cavernosum  penis.  In  the  latter  it  is  familiar  to 
every  practised  anatomist,  that  the  branches  of  the  arteries  are 
but  small,  as  they  terminate  in  the  cells  of  the  penis,  which  are 
to  be  considered  as  only  a  modification  of  the  incipient  stage  of 
venous  trunks.  If  the  corpus  spongiosum  were  in  fact  spread 
out  into  a  thin  membrane,  so  as  to  line  a  hollow  viscus,  it  would 
present  no  very  exaggerated  representation  of  what  I  have  de- 
nominated the  superficial  venous  layer  of  the  alimentry  canal; 
it  being  also  admitted  that  within  the  circuit  of  every  anasto- 
mosis a  follicle  was  formed.  Viewed  on  the  preparations  of  the 
mucous  membrane  of  the  small  and  large  intestines  which  I 
have,  these  follicles  appear  like  puncta  lachrymalia  disseminated 
VOL.  II.— 7 


46  ORGANS  OF  DIGESTION. 

by  thousands  over  every  inch  square,  and  existing  so  invariably 
upon  every  part  that,  as  I  have  stated,  the  smallest  calculation 
of  their  numbers  puts  them  at  from  forty  to  fifty  millions.  It  is 
now  to  be  borne  in  mind,  that  it  is  the  whole  of  this  vascular 
and  follicular  structure,  endowed  with  the  vital  actions  the  most 
important  to  life,  and  presenting  in  the  aggreate  an  area  of  about 
thirteen  square  feet,  the  size  of  a  small  breakfast  table;  whose 
morbid  derangements  constitute  the  essential  features  of  cholera. 
It  has  been  shown  in  some  of  my  dissections,  that  this  ap- 
paratus in  the  progress  of  cholera  is  detached  entirely  from  the 
stomach  and  colon,  in  consequence  of  the  excessive  actions  go- 
ing on  in  them.  The  small  intestines  also,  in  some  of  my  pre- 
parations, exhibit  in  patches  a  similar  phenomena;  but  as  the 
entire  observation  has  been  presented  to  me  in  its  true  light 
only  since  the  disappearance  of  the  disease,  I  have  no  means  of 
ascertaining  the  extent  to  which  they  suffer  in  this  way. 

The  anatomy  of  the  muciparous  system  of  the  alimentary  ca- 
nal unquestionably  requires  a  more  exact  attention  than  has  been 
heretofore  bostowed  upon  it,  especially  so  as  to  distinguish  be- 
tween that  part  which  is  really  glandular,  and  the  foramina  or 
follicles  now  under  consideration.  The  following  extract  will 
explain  the  difficulty  which  still  exists  in  regard  to  a  proper 
conception  of  the  latter. 

"The  mucous  glands,  called  also  follicles  or  cryptse  mucosse, 
are  to  the  membranes  of  that  name  what  the  sebaceous  follicles 
are  to  the  skin;  that  is  to  say,  folds  of  the  mucous  membrane 
in  form  of  a  cul-de-sac,  whose  orifices  open  upon  that  mem- 
brane. These  follicles  have  not  yet  been  discovered  over  the 
whole  surface  of  the  mucous  membrane;  but  here,  as  with  the 
skin,  analogy  leads  us  to  admit  them.  It  is  not  long  since  they 
have  been  discovered  in  the  pituitary  membrane,  where  their 
existence  had  been  denied.  Be  this  as  it  may,  we  shall  use  the 
same  observation  upon  these  glands  that  was  made  on  the  seba- 
ceous, viz.  the  impossibility  of  making  an  exact  dissection  of  the 
capillary  tissues  does  not  allow  us  to  discover  all  the  forms  of 
animal  matter;  but  wherever  a  particular  humour  is  found  in  a  tis- 
sue, we  are  forced  to  conclude  that  this  latter  is  organized  in  such 
a  manner  as  to  be  able  to  produce  it,  and  when  in  place  of  one 
humour  we  meet  with  many,  we  must  acknowledge  that  the 


ANATOMY  OF  THE  MUCOUS  COAT.  47 

tissue  is  complex.  Such  is  precisely  the  case  with  the  mucous 
membrane  of  the  digestive  canal,  and  especially  of  the  stomach, 
which  could  have  a  form  of  animal  matter  calculated  to  furnish 
digestive  juices,  although  no  gland  destined  to  that  purpose  is 
discoverable."* 

This  desideratum  of  positive  evidence,  instead  of  the  induc- 
tive, is  clearly  supplied  to  M.  Broussais  by  my  preparations. 
In  infancy,  especially,  the  glands  have  a  sensible  thickness, 
which  enables  us  to  see  them,  but  the  smallest  of  them  require 
the  aid  of  a  microscope,  and  appear  to  have  been  described  by 
Galeati.t  As  the  paper  is  not  to  be  had  in  any  of  the  public 
libraries  of  this  city,  I  can  only. quote  from  it  on  the  current 
authority  of  anatomical  works.  In  a  note  to  the  anatomy  of  the 
human  body  by  Sir  Charles  Bell,  article  Intestine,  it  is  stated 
as  follows: — "It  has  been  supposed  that  the  fluids  excreted  from 
the  surface  of  the  intestines  were  furnished  by  very  minute  fo- 
ramina, (which  are  visible  by  particular  preparations,)  in  the 
interstices  of  the  villi.  See  the  letter  of  Malpighi  to  the  Royal 
Society  of  London  on  the  pores  of  the  stomach,  and  the  paper 
by  M.  Galeati  in  the  Bologna  Transactions,  on  the  inner  coat, 
which  he  calls  the  cribriform  coat.  The  pores,  according  to  Ga- 
leati, are  visible  through  the  whole  tract  of  the  canal,  and  par- 
ticularly in  the  great  intestines."  Meckel  designates  these  as 
glandular  bodies  under  the  name  of  glandulx  mucosae,  cryptse 
minimae.  Another  order  of  glands  are  those  of  Brunner.J  They 
are  readily  found  in  the  duodenum  at  all  ages;  and  particularly 
well  in  infancy,  as  low  down  as  the  ileo-colic  valve.  The  third 
order  are  the  glands  of  Peyer,  discovered  in  1677. §  The  cele- 
brated Ruysch  appears  also  to  have  understood  the  existence  of 
the  follicles  of  the  stomach,  and  Svvammerdam  to  have  had  some 
idea  of  those  of  the  small  intestines,||  and  he  calls  them  tubuli 
glandulosi  intestinorum  interiores.  I  may  here  remark,  that 
the  account  of  the  villi  of  the  small  intestines  given  by  Hedwig, 

*  Broussais'  Physiology.     First  American  edition,  p.  419. 

-j-  De  cornea  ventriculi  et  intestinorum  tunica.     Comm  Bonon.  1745. 

$  Glandule  intestini  duodeni  vel  pancreas  secundarius;  discovered  in  1715. 
See  Mangetus,  Theat.  Anat.  where  this  paper  is  introduced  with  the  plates  illus- 
trative of  it. 

§  See  also  Mangetus  for  the  description  from  Peyer,  with  his  plates. 

||  Mangetus  Theat.  Anat.  Vol.  I.  p.  310. 


48  ORGANS  OF  DIGESTION. 

in  his  Disquisit.  Ampullarum,  &c.  1797,  and  which  appears, 
from  its  introduction  into  Caldani's  and  M.  Jul.  Cloquet's  Anato- 
my, to  have  a  classical  value,  is,  judging  from  my  own  prepara- 
tions, too  much  a  work  of  the  imagination,  executed  under  pro- 
bably some  fallacious  views  of  the  part  itself:  a  cluster  of  cylin- 
drical villi,  with  holes  at  the  ends,  would  be  an  anomaly,  for 
those  of  the  upper  part  of  the  intestines  are  either  serpentine 
folds,  as  represented  in  my  plates,  with  branches  running  into 
contiguous  folds,  or  semi-oval  laminae;  while  those  lower  down 
are  of  a  flattened  conical  shape,  somewhat  bent,  but  in  every  in- 
stance they  are  destitute  of  what  has  been  termed  by  Lieberkuhn 
an  ampulla,  and  to  my  eye  have  uniformly  polished  surfaces, 
uninterrupted  by  foramina. 

Mascagni  has  also  introduced  views  of  a  good  kind  in  regard 
to  the  follicular  structure  of  the  stomach  and  colon.*  But  it  is  to 
Sir  Everard  Home,  that  we  are  indebted  for  one  of  the  best  papers 
on  the  glandular  structure  of  the  stomach  of  different  animals.t 

As  the  real  muciparous  glands  have  an  orifice  leading  into 
each  by  the  admission  of  anatomists,  the  follicles  described 
commonly  by  them,  are  of  this  description,  and  are  not  compa- 
rable in  number  to  the  follicles  found  in  the  venous  meshes. 
The  highest  estimate  of  the  number  of  the  former,  as  made  by 
M.  Lelut,  fixes  them  about  forty-two  thousand.!  In  consult- 
ing many  of  the  distinguished  modern  authorities  on  this  sub- 
ject, there  seems  to  be  scarcely  any  thing  in  the" anatomy  of  the 
intestinal  canal  which  is  presented  in  a  more  indefinite  way; 
especially  in  regard  to  the  small  intestines,  than  the  difference 
between  the  follicles,  properly  speaking,  and  the  glands;  and 
none  of  them,  so  far  as  I  know,  have  undertaken  to  approximate 
the  entire  number  of  the  follicles. 


SECT.  IV. OF  THE  GENERAL  ANATOMY  OF  THE  MUCOUS  MEMBRANES. 

The  extent  of  the  mucous  coat  of  the  alimentary  canal,  and 
the  important  and  varied  sympathies  which  it  has  with  most 
other  parts  of  the  body,  render  useful  some  remarks  on  mem- 

*  Prodrome  delta  grande  anatomia.    Tab.  xiii. 

f  Phil.  Trans.  1807  and  1817:  and  also  his  Comparative  Anatomy. 

t  Bouillaud,  Tra'rt£  du  Cholera,  p.  256. 


GENERAL  ANATOMY  OF  THE  MUCOUS  MEMBRANES.  49 

branes  of  this  kind  generally.  Mucous  Membranes  are  so  called 
from  the  nature  of  the  secretion  which  they  furnish :  and  the 
term  having  been  first  applied  to  the  lining  coat  of  the  nose,  a 
similitude  of  character  has  caused  its  extension  to  that  of  other 
organs.  The  celebrated  Bichat,  the  founder  of  the  science  of 
general  anatomy,  was  the  first  to  adopt  fully,  and  to  perceive 
the  value  of  this  classification ;  since  which  it  has  been  almost 
universally  received  by  anatomists. 

As  the  skin  forms  an  external  covering  to  the  body,  so  mu- 
cous membrane  lines  the  internal  surface  of  the  hollow  viscera. 
When  it  is  recollected  that  this  membrane  forms  an  internal  in- 
tegument to  the  whole  alimentary  canal,  from  the  mouth  to  the 
anus ;  to  all  of  the  urinary  and  genital  apparatus ;  to  the  whole 
respiratory  system,  from  the  nose  down  the  trachea  and  through- 
out the  lungs ;  it  will  be  admitted  that  its  extension  exceeds  much 
that  of  the  skin. 

A  mucous  membrane  presents  two  surfaces,  one  of  which  ad- 
heres to  the  contiguous  parts,  and  the  other  is  free  by  being  in- 
ternal. The  adherent  surface  is  attached  by  a  cellular  structure 
somewhat  condensed.  This  cellular  structure  is  principally  re- 
markable for  its  want  of  disposition  to  secrete  fat  into  its  inter- 
stices ;  a  property  of  immense  importance,  as  without  it,  ob- 
structions would  be  continually  occurring  to  the  destruction  of 
life  :  it  is  pervaded  by  a  multitude  of  fine  vessels  and  nerves,  run- 
ning forward  to  be  spent  upon  the  mucous  membrane ;  and  has 
been  unfortunately  named  nervous  coat,  by  anatomists  of  high  au- 
thority. The  strength  of  attachment  which  it  furnishes  is  some- 
what varied ;  for  example,  in  the  small  intestinal  canal  I  have 
often  seen  the  mucous  membrane  caught  at  one  end  and  entirely 
withdrawn  from  the  other  coats,  an  experiment  which  alone  can 
give  rigid  ideas  of  its  greater  length,  as  by  it  all  the  duplicatures 
or  valvulae  conniventes  are  stretched  out.  The  experiment  suc- 
ceeds much  more  certainly  by  the  regular  pressure  of  a  column 
of  water  between  the  tunics  of  the  intestine.  The  mucous  mem- 
brane of  most  organs  is  arranged  into  wrinkles  and  duplicatures, 
for  the  purpose  of  augmenting  its  extent.  This  arrangement  pre- 
vails in  the  nose,  and,  as  mentioned,  in  the  oesophagus,  in  the 
stomach  and  intestines ;  to  say  nothing  of  many  other  instances 
which  are  noticed  in  the  description  of  each  organ.  In  some 


50  ORGANS  OF  DIGESTION. 

examples,  they  are  permanent,  and,  in  others,  depend  on  the 
state  of  contraction  of  an  exterior  muscular  coat.  The  interior 
face  of  the  mucous  membranes,  allowance  being  made  for  the 
inequalities  just  stated,  moreover,  presents,  when  closely  viewed, 
an  abundance  of  more  minute  depressions  and  of  elevations, 
causing  it  to  resemble  velvet.  Some  of  these  depressions  are  so 
large  as  to  give  it  a  cellular  appearance,  as  in  many  parts  of  the 
intestinal  canal,  and  the  gall-bladder,  and  have  been  particularly 
described  by  Sir  Everard  Home. 

In  regard  to  organization,  the  mucous  membranes  are  of  a 
soft,  spongy  consistence ;  easily  yield  to  mechanical  violence ; 
and  depend  for  their  strength  upon  the  surrounding  cellular  coat. 
They  are  not  of  a  uniform  thickness ;  for  example,  they  are  much 
thinner  in  the  urinary  and  genital  apparatus,  than  in  the  alimen- 
tary canal ;  they  also  present  some  varieties  of  consistence.  They 
yield  very  readily  to  putrefaction,  and  are  quickly  reduced  to  a 
pulpy  state  by  the  action  of  the  mineral  acids.  Caustics  of  all 
kinds  act  more  promptly  on  them  than  on  the  skin,  owing  to  the 
protection  of  the  latter  by  a  dry  epidermis ;  Bichat  states,  that  in 
the  practice  of  the  Hotel  Dieu,  this  effect  is  frequently  exempli- 
fied, by  the  administration  of  lunar  caustic  among  the  common 
people  for  the  purpose  of  poisoning.  The  nitric  acid  leaving  the 
silver,  quickly  applies  itself  to  the  mucous  membrane  of  the  sto- 
mach, and  disorganizing  it,  forms  a  whitish  eschar,  which,  if  life 
be  preserved  long  enough,  is  finally  detached  in  a  membranous 
form. 

One  of  the  remarkable  properties  of  the  mucous  surfaces  of  the 
stomach  and  intestines  is,  that  of  coagulating  milk.  According 
to  the  experiments  of  Spallanzani,  the  gastric  juice,  in  the  living 
state,  assists  in  this  change;  but  it  is  perfectly  well  known  in  do- 
mes.tic  affairs,  that  the  dried  stomach  of  a  calf,  where  the  juices 
have  been  completely  evaporated,  is  also  productive  of  it.  The 
observations  of  the  same  author  led  him  to  conclude,  that  the 
peritoneal  and  the  muscular  tunics  of  the  stomach  are  insufficient 
to  produce  this  effect. 

The  internal  surface  of  all  the  mucous  membranes  is  furnished 
with  small  projecting  points  or  spiculae,  called  papillae  or  villi. 
They  are  particularly  conspicuous  and  numerous,  as  mentioned, 
on  the  upper  surface  of  the  tongue  and  in  the  small  intestine, 


GENERAL  ANATOMY  OF  THE  MUCOUS  MEMBRANES.        51 

and  bear  an  analogy  of  function  and  organization  with  the  very 
fine  papillae  which  are  seen  invariably  on  the  surface  of  the 
cutis  vera.  These  papillae  are  invariably  furnished  with  ner- 
vous filaments,  giving  them  a  high  degree  of  sensibility;  and 
with  an  abundance  of  blood  vessels.  The  term  papillae  has  been 
more  exclusively  applied  to  the  projections  on  the  surface  of  the 
tongue,  from  their  greater  size ;  they  are  there  also  more  distinctly 
covered  with  an  epidermis,  frequently  called  epithelium,  or  peri- 
glottis.  The  villi-,  from  their  connexion  with  the  process  of  di- 
gestion, have  been  emphatically  denominated  the  roots  of  ani- 
mals. According  to  M.  Beclard,*  who  has  examined  them  upon 
a  plan  of  his  own  contrivance  well  suited  to"  accurate  microsco- 
pal  observations,  they  are  presented  under  a  diversity  of  shapes. 
Those  of  the  pyloric  half  of  the  stomach,  and  of  the  duodenum 
being  broader  than  they  are  long,  are  composed  of  very  small 
thin  laminae,  having  a  tufted  arrangement.  Those  of  the  jeju- 
num are  long  and  narrow,  having  more  the  form  commonly 
assigned  to  them,  while  in  the  lower  part  of  the  ileum  and  in 
the  colon  they  again  become  laminated. 

It  should  be  observed  that  notwithstanding  the  assertion  of 
Lewenhoeck,  Hewson,  Hunter,  and  others,  the  fact  is  still  called 
in  question,  by  two  of  the  most  distinguished  anatomists  of  the 
present  time,  MM.  Beclard  and  J.  F.  Meckel,  whether  the  orifices 
of  the  lacteals  are,  under  any  circumstances,  visible  on  the  sur- 
face of  the  villi.  Admitting  that  they  do  not  open  as  stated,  the 
power  of  interstitial  absorption  in  the  mucous  membrane  will 
still  account  for  the  chyle  finally  getting  into  the  lacteals,  as  well 
as  for  fluids  passing  into  the  circulation  from  the  stomach,  when 
its  continuity  with  the  intestinal  canal  has  been  interrupted.t 

The  Epidermis  or  Epithelium  of  mucous  membranes  is  very 
distinct  at  their  external  orifices,  but  becomes  less  and  less  ap- 
parent towards  the  interior  of  the  body,  until  finally  it  cannot  be 
distinguished;  and  anatomists  generally  consider  that  it  is  entirely 
deficient,  notwithstanding  the  assertion  of  Haller  to  the  contrary. 
It  is  a  matter  of  common  observation,  that  when  the  interior  of 
mucous  membranes  is  exposed  by  an  eversion  for  a  long  time,  to 

*  Anat.  Gen.  p.  253. 

•j-  Should  the  suggestion  of  the  absorbing  powers  of  the  gastro-enteric  follicles 
which  I  have  proposed  in  Section  third,  be  correct,  it  will  dispose  of  the  diffi- 
culties and  opposing  opinions  alluded  to  in  this  paragraph, 


52  ORGANS  OF    DIGESTION. 

the  action  of  the  atmosphere ;  they  take  on  more  of  the  structure 
of  skin,  and  become  evidently  covered  with  a  cuticle  which  pro- 
tects them  and  diminishes  their  secretion.  This  is  exemplified 
in  eversion  of  the  vagina  from  prolapsed  uterus,  in  elongated  and 
tumid  labia  interna,  and  in  other  ways:  restore  the  parts  to  their 
natural  situation,  and  they  are  brought  back  to  their  original 
structure.  In  the  partial  prolapse  of  the  mucous  membrane  of  the 
rectum,  from  piles,  corresponding  circumstances  occur.  From 
this  we  infer,  that  the  full  development  of  cuticle  depends  very 
much  upon  the  degree  of  exposure  which  any  surface  of  the 
body  has  to  undergo.  The  reverse  also  takes  place:  shut  up  or 
close  any  surface  of  the  skin  so  that  it  is  put  in  the  condition  of 
an  interior  cavity,  and  it  immediately  begins  to  assimilate  it- 
self to  a  mucous  membrane.  This  is  proved  by  the  tendency  in 
young  children  to  a  detachment  of  the  cuticle,  or  excoriation  of 
the  opposed  surfaces  of  the  deep  wrinkles  about  their  thighs  and 
in  their  perineum ;  a  tendency  obviated  by  the  practice  of  nurses 
of  covering  these  surfaces  with  powdered  starch.  It  is  also 
manifested  frequently  in  the  dressing  of  wounds  with  sticking 
plaster,  where  an  incautious  approximation  of  the  contiguous 
surfaces  of  the  skin,  not  only  is  followed  by  excoriation,  but  even 
'by  ulceration;  a  fact,  the  importance  of  which  was  formerly  set 
in  proper  relief  by  Dr.  Physick  in  his  surgical  lectures,  and  of 
which  I  have  seen  an  example  in  a  case  of  extirpated  female 
mamma.  The  state  of  this  question  is,  in  fine,  such  that  I  think 
we  may  safely  admit  the  existence  of  a  very  thin  epidermis  on 
the  alimentary  canal,  but  so  pulpy  that  it  cannot  be  distinguished 
except  by  the  process  alluded  to  in  Section  third  of  this  Chapter. 

The  mucous  membranes  vary  in  colour  from  a  very  light  pink 
to  a  deep  red,  which  is  owing  to  the  blood  that  circulates  in 
them.  In  cases  of  suffocation,  they  become  almost  brown  from 
the  congestion  of  blood  in  them,  while  in  fainting  they  turn  white 
from  the  desertion  of  the  latter.  These  vessels  after  having  pe^ 
netrated  the  thickness  of  the  membrane,  ramify  with  extreme 
minuteness  on  its  surface.  In  consequence  of  this  superficial  si- 
tuation, the  vessels  being  unsupported  on  one  side,  are  exposed 
to  rupture  from  slight  concussions;  in  this  way  hemorrhage  is 
produced  in  the  lungs  from  coughing,  and  bleeding  at  the  nose 
from  blows  upon  the  head. 


GENERAL  ANATOMY  OF  THE  MUCOUS  MEMBRANES.        53 

Exhalent  orifices  exist  in  great  numbers  in  the  mucous  mem- 
branes :  this  is  especially  the  case  in  the  lungs,  where  the  pul- 
monary perspiration,  as  it  is  called,  is  very  obvious  to  common 
observation.  Elsewhere,  this  discharge  is  so  much  blended  with 
the  mucus  of  the  part,  that  it  is  difficult  to  appreciate  its  quantity. 
From  the  superficial  situation  of  the  blood  vessels,  it  is  clear  that 
the  exhalent  orifices  or  pores,  have  but  a  short  course  to  run. 
This  is  considered  by  Bichat  as  a  satisfactory  reason  for  the 
tendency  of  the  blood  to  escape  through  them,  or  to  ooze  out 
where  there  is  no  rupture. 

Absorbents  exist  also  in  great  numbers,  as  proved  by  the  ab- 
sorption of  chyle,  of  watery  drinks  from  the  intestinal  canal,  and 
by  the  inhalation  of  the  vapour  of  spirits  of  turpentine  into  the 
lungs,  rapidly  communicating  the  particular  smell  of  this  article 
to  the  urine.  There  are,  moreover,  cases  recorded  of  obstructed 
urethra,  where  the  urine  has  been  almost  entirely  absorbed  by 
the  mucous  coat  of  the  bladder. 

In  regard  to  nerves,  the  mucous  membranes  are  well  furnished 
with  them.  Bichat  has  remarked  that  wherever  these  mem- 
branes are  situated  near  the  surface  of  the  body  and  enjoy  com- 
mon sensibility,  they  are  almost  wholly  furnished  from  the  cen- 
tral portions  of  the  nervous  system,  as  the  brain  and  spinal 
marrow:  this  is  exemplified  in  the  conjunctiva,  the  pituitary 
membrane,  the  palate,  the  glans  penis,  &c.  On  the  contrary, 
the  sympathetic  nerve  furnishes  the  intestines,  the  bladder,  and 
the  excretory  tubes  generally. 

Mucous  Glands,  as  they  are  called,  exist  throughout  the  sys- 
tem of  mucous  membranes,  being  situated  either  under  them  or 
in  their  thicknesses.  From  them  is  derived  the  mucilaginous 
fluid  which  lubricates  so  abundantly  their  interior  surfaces,  so 
as  to  facilitate  the  passage  of  extraneous  bodies,  and,  at  the 
same  time,  to  protect  the  membrane  from  mechanical  violence. 
These  glands  are  of  various  sizes,  from  that  of  the  tonsils  and 
the  muciparous  glands  on  the  lips,  cheeks,  and  root  of  the  tongue, 
to  the  almost  imperceptible  cryptae  of  the  bladder  and  urethra. 
Their  shape  is  either  lenticular,  rounded,  or  that  of  a  pouch. 
The  two  former  have  their  parietes  of  a  sensible  thickness,  but 
the  last  are  too  thin,  to  be  distinguished  from  the  mucous  mem- 
brane itself.  For  the  most  part,  the  excretory  duct  of  these 

VOL.  II.— 8 


54  ORGANS  OF  DIGESTION. 

glands  is  short  and  patulous,  so  as  to  lead  directly  into  the  sub- 
stance of  the  gland.  This  is  remarkably  the  case  with  the  ton- 
sils, which  consist  in  a  congeries  of  these  follicles ;  and  with  the 
glands  on  the  root  of  the  tongue.  In  some  animals  they  are  so 
numerous  as  to  form  almost  a  distinct  lamina  to  the  intestines ; 
after  the  manner  of  the  human  subject,  on  the  palate  and  parietes 
of  the  mouth. 

The  Mucosity  discharged  from  these  glands  is  one  of  the  prin- 
ciples of  animals,  and,  as  is  well  known,  exists  also  to  a  great 
extent  in  some  vegetables.  When  perfectly  pure  and  fluid,  it  is 
white,  transparent,  inodorous,  and  insipid.  It  is  insoluble  in  al- 
cohol, but  soluble  in  acids.  Water  forms  more  than  nine-tenths 
of  it,  the  remainder  is  mucus,  properly  speaking,  blended  with 
some  neutral  salts  of  soda  and  potash. 

The  mucous  membranes  are  exposed  to  a  multitude  of  mor- 
bid alterations,  such  as  polypus,  scirrhus,  cancer,  phlegmor- 
rhagiae  or  serous  fluxes,  blennorrhagiae  or  mucous  fluxes,  inflam- 
mation in  all  its  forms,  gangrene,  ulcerations,  and  congestions. 


CHAPTER  IV. 

OF  THE  ASSISTANT  CHYLOPOIETIC  VISCERA. 
SECT.  I. OF  THE  LIVER. 

THE  Liver  (Hepar,  Jecur]  secretes  the  Bile,  and  is  the  largest 
glandular  body  in  the  human  frame.  It,  as  mentioned,  occupies 
the  whole  of  the  right  hypochondriac  region,  the  upper  half  of 
the  epigastric,  and,  as  it  becomes  thinner  in  going  towards  the 
left  side,  it  occupies  a  small  space  in  the  right  superior  part  of 
the  left  hypochondriac  region.  Its  whole  superior  face  is  in 
contact  with  the  diaphragm;  on  the  left  it  is  bounded  by  the 
spleen,  and  below  by  the  stomach  and  the  transverse  colon ;  be- 
hind it,  are  the  vertebral  column  and  the  ascending  cava. 

The  shape  of  the  liver  is  like  one  half  of  an  ovoidal  body  cut 
into  two  in  *the  direction  of  its  long  diameter,  and  having  the 
thick  end  turned  to  the  right  side.  It  is  about  ten  inches  in 


THE  LIVER.  55 

length  by  six  or  seven  wide,  and  weighs  from  four  to  five  pounds 
in  the  adult.  Its  colour  is  a  reddish  brown,  generally;  though, 
on  its  under  surface  and  about  its  edges,  broad,  blue  or  black 
patches  are  constantly  met  with,  which  do  not  indicate  any 
morbid  derangement. 

Its  upper  surface  is  of  a  uniform  convexity,  rather  more  pro- 
minent at  the  right  posterior  part  than  elsewhere;  adjusts  itself 
accurately  into  the  concavity  made  by  the  under  surface  of  the 
diaphragm;  and  is  unequally  divided  from  before  backwards  by 
the  suspensory  ligament.  The  anterior  margin  is  thin,  and  is 
notched  where  the  suspensory  ligament  begins ;  the  posterior 
margin  is  much  thicker,  and  has  near  its  middle  a  broad  de- 
pression, to  fit  it  to  the  projection  of  the  vertebral  column.  The 
ascending  vena  cava  forms  a  superficial  sulcus  upon  this  mar- 
gin, and  frequently  there  is  a  complete  canal  through  the  sub- 
stance of  the  liver  for  transmitting  it.  The  right  extremity  is 
very  thick,  and  almost  fills  the  hypochondriac  region  of  that 
side,  while  the  left  extremity  is  reduced  to  a  thin,  tapering,  and 
flexible  edge. 

The  under  surface  of  the*  liver  is  much  more  irregular  than 
the  upper;  it  is  traversed  in  an  antero  posterior  direction,  in  a 
line  corresponding  with  the  attachment  above  of  the  suspensory 
ligament,  by  the  umbilical  fissure,  (Sulcus  Umbilicalis)  which 
extends  from  the  notch  in  the  front  edge  to  the  depression  be- 
hind, and  obtains  its  name  from  having  accommodated  in  the 
fcetal  state,  the  umbilical  vein,  now  converted  into  a  round  liga- 
mentous  cord.  In  the  posterior  part  of  this  fissure  is  likewise  to 
be  seen,  in  the  same  condition,  what  remains  of  the  ductus  ve- 
nosus.  The  anterior  portion  of  the  umbilical  fissure  is  not  un- 
frequently  converted  into  a  complete  canal,  by  a  portion  of  he- 
patic substance  crossing  it  like  a  small  bridge.  The  transverse 
fissure  (Sulcus  Transversus,  Intermedius]  is  situated  in  the  middle 
of  the  under  surface  of  the  liver,  and  extends  along  a  third  or 
fourth  of  the  long  diameter  of  the  latter.  It  begins  somewhat  to 
the  left  of  the  umbilical  fissure,  and  crossing  it  at  right  angles, 
proceeds  towards  the  right  extremity.  It  contains  the  vena  por- 
tarum,  the  hepatic  artery,  and  the  hepatic  duct ;  all  of  which 
are  bound  to  each  ether  by  a  close  cellular  substance.  • 

The  suspensory  ligament  above,  and  the  umbilical  fissure  be- 


56  ORGANS  OF  DIGESTION. 

low,  give  occasion  to  divide  the  liver  into  Lobes;  right  and  left; 
of  which  the  right  is  by  much  the  largest,  and  accommodates 
almost  entirely  the  transverse  fissure,  having  also  on  its  under 
surface  some  subordinate  elevations,  to  wit,  the  Lobulus  Spigelii 
and  the  Lobulus  Quartus,  together  with  the  Gall-Bladder. 

The  Lobulus  Spigelii  is  placed  between  the  transverse  fissure 
and  the  posterior  margin  of  the  liver,  to  the  right  of  the  poste- 
rior end  of  the  umbilical  fissure.  Its  shape  is  somewhat  prisma- 
tic, bifurcating  in  front ;  one  of  the  elongations  is  a  papilla  over- 
hanging the  transverse  fissure,  and  is,  therefore,  considered  as 
one  side  of  the  gateway  (porta)  opened  for  the  vena  portarum ; 
the  other  elongation  is  a  small  ridge,  sometimes  called  Lobulus 
Caudatus,  and  is  lost  gradually  on  the  under  surface  of  the  great 
lobe,  by  inclining  to  the  right. 

The  Lobulus  Quartus,  or  Anonymus,  is  not  by  any  means  so 
elevated  as  the  last,  but  having  a  flattened  surface,  is  placed  in 
front  of  the  transverse  fissure,  between  the  fore  end  of  the  um- 
bilical fissure  and  the  gall-bladder ;  its  posterior  extremity  is  the 
second  porta  of  the  Liver,  and  is  just  opposite  to  that  furnished 
by  the  Lobulus  Spigelii. 

The  liver,  from  being  completely  enveloped  in  peritoneum,  has 
a  smooth  glossy  appearance.  The  reflections  of  this  membrane, 
from  it  to  the  parietes  of  the  abdomen,  form  the  ligaments,  as 
they  are  called,  which  consist  each  of  two  laminae.  The  Fal- 
ciform Ligament,  or  Suspensory,  containing  in  its  anterior  mar- 
gin *the  remains  of  the  umbilical  vein,  now  called  Ligamen- 
tum  Teres,  begins  at  the  umbilicus,  extends  from  it  along  the 
linea  alba  and  the  middle  line  of  the  diaphragm,  and,  as  men- 
tioned, is  reflected  to  the  upper  surface  of  the  liver,  from  the  an- 
terior to  the  posterior  margin.  The  Right  Lateral  Ligament  is 
situated  behind,  and  departs  from  the  back  part  of  the  diaphragm 
to  the  posterior  margin  of  the  right  lobe.  The  Left  Lateral  Li- 
gament also  goes  from  the  back  part  of  the  diaphragm,  and  is 
attached  along  the  posterior  margin  of  the  left  lobe.  Where  the 
suspensory  ligament  inclines  on  each  side  into  the  lateral,  it 
passes  with  so  much  obliquity  as  to  leave  some  portion  of  the 
posterior  margin  of  the  liver  uncovered  by  peritoneum ;  the  lat- 
ter, where  it  describes  the  periphery  of  this  space,  has  been  ra- 
ther unnecessarily  designated  as  the  Coronary  Ligament. 


THE  LIVER.  57 

In  addition  to  the  peritoneal  coat,  the  liver  has  another,  con- 
necting it  with  the  peritoneum,  and  seeming  to  be  only  condensed 
cellular  substance,  which  also  penetrates  into  the  substance  of 
the  gland,  and  holds  its  constituent  parts  together.  It  is  parti- 
cularly well  seen  within  the  circle  of  the  coronary  ligament. 


Of  the  Organization  of  the  Liver. 

The  Liver  is  made  extremely  vascular  by  the  ramifications  of 
three  kinds  of  blood  vessels,  the  vena  portarum,  the  Hepatic  Arte- 
ry, and  the  Hepatic  Veins.  The  two  first  convey  the  blood  to 
it,  and  the  third  removes  it  again,  into  the  general  circulation,  by 
emptying  into  the  ascending  vena  cava.  There  are  also  branches 
of  the  hepatic  duct,  lymphatic  vessels,  and  nerves. 

The  glandular  substance  is  fragile  and  easily  lacerated ;  when 
torn  it  assumes  the  appearance  of  a  congeries  of  spherical  or  po- 
lyhedrical  grains,  called  acini  from  their  resemblance  to  small  ber- 
ries: they  are  united  in  mass  by  the  elongations  of  the  cellular 
coat,  and  traversed  by  the  trunks  of  the  blood  vessels.  Each  of 
these  granulations  is  about  the  size  of  a  millet  seed,  and  is  a  re- 
presentative of  the  entire  gland,  as  its  structure  is  complete  in 
itself;  being  formed  by  the  terminations  of  the  blood  vessels,  and 
by  the  origin  of  a  branch  of  the  hepatic  duct,  called  the  porus 
biliarius.  When  examined  with  a  microscope,  it  is  said  that 
these  acini  are  composed  of  a  yellow  and  of  a  brown-looking  sub- 
stance ;  it  has  not,  however,  occurred  to  me  to  see  the  distinction 
in  a  very  satisfactory  way,  though  it  is  recognised  by  anatomists 
of  high  authority.* 

The  Vena  Portarum  having  arisen  from  the  junction  of  all 
the  veins  of  the  stomach,  intestines,  pancreas  and  spleen,  is 
about  three  inches  in  length  when  it  reaches  the  transverse  fis- 
sure, by  going  over  the  duodenum  and  under  the  pancreas.  It 
immediately  divides  into  two  branches,  called  collectively  the 
Sinus  Venae  Portarum,  which  is  at  right  angles  with  the  trunk 
of  the  vein;  the  right  branch  being  the  shortest  and  largest,  is 
distributed  by  radiating  trunks  to  the  right  lobe  of  the  liver; 

*  Bichat,  Meckel,  &c, 


58  ORGANS  OF  DIGESTION. 

the  left  branch  is  distributed,  after  the  same  manner,  to  the  left 
lobe,  to  the  lobulus  spigelii,  and  to  the  lobulus  quartus.  Some 
of  its  branches  anastomose  with  the  hepatic  veins,  which  ac- 
counts for  the  ease  with  which  an  injection  will  pass  from  one 
to  the  other.  Other  branches  of  a  smaller  description  anasto- 
mose with  the  pori  biliarii,  but  with  less  freedom  than  in  the 
preceding  case;  and  lastly,  the  most  delicate  ramifications  are 
spent  upon  the  cortical  or  yellow  matter  of  the  acini,  without 
penetrating  to  the  brown.* 

The  Hepatic  Artery  is  a  branch  of  the  cceliac,  and  in  ap- 
proaching the  transverse  fissure  divides  into  three  or  more 
branches,  that  penetrate  the  substance  of  the  liver,  between  the 
sinus  portarum  and  the  ducts  as  they  come  out;  one  branch 
goes  to  the  right  lobe,  another  to  the  left,  and  a  third  to  the 
lobulus  spigelii.  There  is  some  variety  in  regard  to  the  precise 
mode  of  distribution,  and  their  division  into  subordinate  rami- 
fications frequently  occurs  before  they  get  fairly  into  the  sub- 
stance of  the  liver.  When  there,  they  seem  to  be  intended  for 
the  nourishment  of  this  organ,  according  to  the  observations  of 
several  able  anatomists;  and  follow  the  ramifications  of  the  vena 
portarum  and  of  the  biliary  ducts,  forming  upon  them  a  very 
delicate  and  complicated  tissue  of  anastomosing  vessels;  some 
of  which,  probably  the  vasa  vasorum,  communicate  with  the 
vena  portarum. 

The  Biliary  Pores  (Pori  Biliarii}  or  the  commencing  rami- 
fications of  the  biliary  duct,  take  their  origin  in  the  acini;  and, 
as  is  said,  upon  the  boundary  between  the  two  kinds  of  matter, 
avoiding  the  brown  and  passing  through  the  cortical. t  The 
larger  branches  converge  into  their  respective  trunks  succes- 
sively or  in  pairs;  while  the  primordial,  or  most  minute  ones, 
converge  several  of  them  to  the  same  point,  giving  a  penicillous 
appearance.  It  is  asserted  that  a  fine  injection  passes  more 
readily  from  them  into  the  lymphatics  than  into  any  other  order 
of  vessels;  which  may  account  for  the  promptitude  of  jaundice 
upon  an  obstruction  of  the  hepatic  duct. 

*  Mnppes,  I.  F.  Meckel,  loc.  cit; 
t  I.  F.  Meckel,  loc.  cit. 


THE  LIVER.  59 

The  Hepatic  Veins  arise  in  the  acini  from  the  capillary  ter- 
minations of  the  vena  portarum  and  the  hepatic  artery.  Their 
hranches  are  sucessively  accumulated  into  three  large  trunks, 
the  collective  area  of  which  vastly  exceeds  that  of  the  vessels 
bringing  the  blood  to  the  liver.  Two  of  these  trunks  come 
from  the  right  lobe  and  one  from  the  left,  to  empty  into  the 
ascending  cava,  while  it  is  still  in  contact  with  the  liver,  im- 
mediately below  the  diaphragm;  just  below  the  preceding  trunks 
there  are  five  or  six,  sometimes  more,  small  hepatic  veins, 
coming  from  the  posterior  margin  of  the  liver,  and  from  the 
lohulus  spigelii.  The  hepatic  veins  are  destitute  of  valves,  and 
remarkable  for  the  thinness  of  their  parietes.  An  injection 
passes  readily  from  them  into  the  other  systems  of  vessels. 
They  may  be  recognised  by  their  insulated  course,  by  their 
consisting  in  trunks  which  converge  from  the  periphery  of  the 
liver  to  the  vena  cava,  while  all  the  other  vessels  diverge  from 
the  transverse  fissure  to  the  periphery,  and  consequently  cross 
the  course  of  the  hepatic  veins. 

At  the  bottom  of  the  transverse  fissure  of  the  liver  is  to  be 
found  a  condensed  cellular  fibrous  tissue,  which  invests  the  vena 
portarum,  the  hepatic  artery,  and  the  biliary  ducts ;  and,  as  they 
all  keep  together  in  their  ramifications,  this  tissue  follows  them 
throughout  the  substance  of  the  liver,  and  thereby  forms  sheaths 
for  them.  It  may  be  considered  as  continuous  with  the  processes 
sent  in  from  the  cellular  coat ;  and,  contrary  to  the  opinion  of 
Glisson,  whose  capsule  it  has  been  called,  it  is  devoid  of  muscu- 
lar structure.* 

Of  the  Gall  Bladder. 

The  Gall  Bladder  (Cistis  Fellea)  is  a  reservoir  for  the  bile  se- 
creted by  the  liver.  It  is  fixed  on  the  under  surface  of  the  great 
lobe,  to  the  right  of  the  umbilical  fissure,  and  removed  from  the 
latter  by  the  lobulus  quartus.t  It  is  an  oblong  pyriform  sac, 

*  An  elaborate  work  on  the  minute  anatomy  of  the  liver  has  lately  appeared, 
from  the  English  press,  by  Francis  Kiernan,  Esq.  R.  C.  Surgeons,  London,  1833, 
in  which  there  are  some  peculiar  notions  of  structure.  It  is  highly  creditable  to 
the  zeal  of  the  author  and  well  worthy  of  perusal. 

j-  I  have  seen  an  instance  where  it  was  to  the  left  of  the  umbilical  fissure,  on 
the  small  lobe.  The  latter  was  much  longer  than  common.  Dec.  1 830. 


60  ORGANS  OF  DIGESTION. 

having  its  anterior  extremity  or  fundus  projecting  somewhat  be- 
yond the  anterior  margin  of  the  liver,  while  the  posterior  end 
reaches  to  the  transverse  fissure.  Its  long  diameter  inclines 
slightly  to  the  right  side,  so  that  it  is  not  precisely  in  an  ante- 
ro-posterior  line.  It  varies  in  its  shape  in  different  subjects,  be- 
ing much  more  spheroidal  in  some  than  in  others.  Its  fundus 
is  rounded  and  obtuse,  while  the  posterior  end  is  gradually  re- 
duced to  a  narrow  neck,  which  is  bent  up  on  itself,  so  as  to  re- 
tard the  flow  of  a  fluid  through  it.  Its  upper  surface  is  in  con- 
tact with  the  substance  of  the  liver,  and  is  received  into  a  broad 
shallow  fossa,  while  the  lower  surface  is  projecting,  and  by 
coming  in  contact  with  the  transverse  colon,  tinges  it  with  bile, 
by  transudation  after  death. 

The  Gall  Bladder  has  three  coats,  a  peritoneal,  a  cellular,  and 
a  mucous  one. 

The  Peritoneal  Coat  is  not  complete,  but  only  covers  that  part 
of  the  sac  not  received  into  the  fossa  on  the  under  surface  of  the 
liver ;  it  is,  therefore,  a  continuation  of  the  peritoneal  coat  of  the 
latter ;  sometimes,  however,  the  gall  bladder  is  so  loosely  at- 
tached to  the  liver  that  it  almost  hangs  off  from  it,  in  which  case 
the  peritoneal  coat  is  nearly  complete. 

The  second  coat  is  condensed  cellular  membrane.  Through 
it  ramifies  a  great  number  of  lymphatics,  and  blood  vessels ;  be- 
low, it  attaches  the  peritoneal  to  the  mucous  coat,  and  above, 
the  latter  to  the  liver. 

The  Mucous  Coat  is  alwrays  tinged  of  a  deep  green  or  yellow, 
by  the  bile  which  it  contains  percolating  after  death ;  for  it  is 
said  to  be,  before  that,  of  a  light  colour.  This  coat  is  thrown 
into  irregular  tortuous  folds  or  wrinkles  of  extreme  delicacy,  in 
the  intervals  of  which  are  many  round  or  polyhedrous  cells, 
causing  it  to  look,  when  floated  in  water,  like  a  fine  honey  comb; 
such  as  are  about  the  fundus  of  the  sac  are  superficial,  and  not 
so  distinct ;  but  those  near  its  middle  and  about  the  neck,  are  a 
line  or  a  line  and  a  half  deep.  In  the  neck  or  apex,  and  in  the 
beginning  of  the  cystic  duct,  are  from  three  to  seven,  sometimes 
twelve,  semilunar  duplicatures  of  the  internal  membrane,  which 
also  retard  the  flux  and  afflux  of  any  fluid,  though  they  do  not 
afford  so  much  resistance  to  the  ingress  as  to  the  egress  of  it. 


THE  LIVER.  61 

These  duplicatures  are  sometimes  arranged  into  a  spiral  valve, 
projecting  from  the  inside  of  the  duct,  and  forming  two  or  three 
turns.*  Very  small  mucous  follicles  exist  over  the  internal  face 
of  this  membrane,  the  discharge  of  which  fills  the  gall  bladder 
when  the  secretion  of  bile  has  been  interrupted  by  diseased  ac- 
tion, as  in  yellow  fever,  or  by  scirrhus  of  the  liver. 

The  artery  of  the  gall  bladder  is  a  branch  of  the  hepatic.  Its 
veins  empty  into  the  vena  portarum.  Its  nerves  come  from  the 
sympathetic,  and  its  lymphatics  join  those  of  the  liver. 

Of  the  Biliary  Ducts. 

A  succession  of  very  fine  branches  having  arisen  from  the  aci- 
ni of  the  liver,  these  branches  are  united  into  three  or  four  trunks 
by  the  time  they  reach  the  transverse  fissure.  These  trunks  then 
coalesce  into  a  single  one,  the  Hepatic,  of  eighteen  or  twenty 
lines  in  length,  and  about  the  diameter  of  a  writing-quill.  The 
Hepatic  Duct  is  then  joined  at  a  very  acute  angle  with  the  duct 
from  the  gall-bladder,  which  is  somewhat  shorter  and  smaller ; 
the  union  of  the  two  forms  the  Common  Duct,  (Ductus  Commu- 
nis  Choledochus.)  The  latter  is  larger  than  either  of  the  others 
singly,  and  is  three  or  three  and  a  half  inches  long ;  it  descends 
behind  the  right  extremity  of  the  pancreas  through  its  substance, 
passes  for  an  inch,  obliquely,  between  the  coats  of  the  duodenum, 
becoming  at  the  same  time  diminished  in  diameter ;  and,  finally, 
ends  by  an  orifice  still  more  contracted,  on  the  internal  face  of 
this  gut,  on  its  second  turn,  and  about  three  or  four  inches  from 
the  stomach.  The  orifice  is  marked  by  a  small  surrounding  tu- 
bercle somewhat  obscured  by  the  valvulae  conniventes. 

The  Biliary  Ducts  are  situated,  as  mentioned,  along  the  right 
margin  of  the  lesser  omen  turn,  and  have  the  vena  portarum  and 
the  hepatic  artery  to  their  left. 

The  bile  ducts  are  formed  by  two  coats;  the  external  is  a 
fibrous,  lamellated,  and  very  extensible  membrane,  while  the  in- 
ternal is  mucous,  having  the  same  structure  with  that  of  the  gall 
bladder,  of  which  it  is  in  direct  continuation.  In  the  Cystic  Duct, 

*  Discovered  latterly  by  M.  Amussat  of  Paris.     M.  Amussat  has  also  detected 
muscular  fibres  in  the  gall  bladder  and  biliary  ducts,  in  which  we  see  an  analogy 
with  other  hollow  viscera. — Am.  Med.  Jour.  vol.  ii.  p.  193, 
VOL.  II.— 9 


92  ORGANS  OF  DIGESTION. 

and  at  the  lower  part  of  the  Common  Duct,  are  several  longitu- 
dinal folds.  The  Common  Duct  sometimes  receives,  just  before 
it  empties  into  the  duodenum,  the  Pancreatic  Duct. 


Of  the  Bile. 

This  secretion  from  the  liver,  is  of  a  deep  yellow,  sometimes 
green  colour :  when  recent,  it  is  thin  and  fluid ;  but  after  it  has 
been  conveyed  to  the  gall  bladder,  and  permitted  to  remain  there 
for  some  time,  it  becomes  as  thick  as  molasses,  and  increases  also 
in  the  intensity  of  its  colour  and  in  bitterness.  Some  anatomists 
have  believed  that  there  was  a  more  direct  communication  be- 
tween the  liver  and  the  gall  bladder  than  that  through  the  hepa- 
tic and  the  cystic  duct ;  but  repeated  and  close  observations  have 
proved  the  opinion  to  be  erroneous,  or,  at  least,  destitute  of  pro- 
per proof:  it  is,  therefore,  clear,  that  the  difference  between  the 
hepatic  and  the  cystic  bile,  depends  upon  the  watery  particles 
being  removed  from  the  latter  by  the  absorbing  power  of  the  in- 
ternal coat  of  the  gall  bladder. 

According  to  Berzelius,  the  chemical  analysis  of  bile  furnishes 
about  eighty  parts  of  water,  eight  of  a  particular  substance  which 
assumes  a  resinous  condition  on  the  application  of  an  acid :  three 
of  mucus ;  and  nine  of  saline  matters ;  of  which  soda  is  a  princi- 
pal constituent. 

SECT.  II. OF  THE  SPLEEN. 

The  Spleen  (Lien.  Splen)  is  situated  deeply  in  the  posterior 
part  of  the  left  hypochondriac  region,  and  is  bounded  above  by 
the  diaphragm,  below  by  the  colon,  and  on  the  right  by  the  great 
end  of  the  stomach,  and  by  the  pancreas.  It  is  not  ascertained 
that  it  secretes  any  thing. 

Its  colour  varies  from  a  deep  blue  to  a  dark  brown.  In  shape 
it  resembles  the  longitudinal  section  of  an  oval,  being  flat  or  very 
slightly  concave  on  the  surface  next  to  the  stomach,  and  convex 
on  that  contiguous  to  the  diaphragm.  Occasionally  its  margins 
are  notched,  but  this  is  not  invariably  the  case.  Its  flat  surface 
is  slightly  depressed  longitudinally  in  the  centre,  where  the  blood 
vessels  enter  it  by  six  or  eight  foramina. 


THE  SPLEEN.  63 

Several  spleens  sometimes  exist  in  the  same  individual,  in  which 
case  the  supernumerary  ones  are  not  larger  than  nutmegs.  The 
common  size  of  this  organ  is  about  four  and  a  half  inches  long, 
by  two  and  a  half  or  three  wide,  in  which  case  it  has  a  solid 
firm  feel ;  but  it  very  often  exceeds  these  dimensions ;  its  transi- 
tion and  varieties  of  magnitude  are  so  frequent,  that  no  settled 
rule  can  be  established.  In  its  inordinate  enlargements  I  have 
seen  it  only  slightly  smaller  than  the  liver,  its  texture  in  this  case 
is  soft  and  easily  lacerated. 

It  is  fixed  in  its  place  by  three  lines  of  reflection  or  processes 
of  peritoneum,  whose  names  indicate  sufficiently  their  places  of 
attachment.  They  are  the  Gastro-Splenic  Ligament  or  Omen- 
turn,  in  which  are  the  vasa  brevia  of  the  stomach ;  the  Splenico- 
Phrenic ;  and  the  Splenico-Colic.  These  reflections,  by  being 
continued  over  the  spleen,  give  it  a  complete  peritoneal  coat, 
which  is  raised  up  with  more  difficulty  than  the  corresponding 
membrane  of  any  other  viscus  of  the  abdomen,  and  is  common- 
ly thrown  into  very  small  inequalities  or  wrinkles. 

The  internal  or  proper  coat  of  the  spleen  is  a  grayish,  com- 
pact, extensible,  and  elastic  membrane,  the  use  of  which  is  evi- 
dently to  sustain  the  natural  shape  of  the  organ,  and  to  support 
its  parenchymatous  structure.  It  sends  in  processes  to  accom- 
pany the  blood  vessels,  and  from  its  internal  face  there  proceeds 
a  multitude  of  lamellae  and  of  fibres,  which  traverse  its  cavity 
in  every  direction,  and  reduce  it  into  a  cellular  condition,  not 
unlike  the  spongy  structure  of  bones. 

The  spleen,  in  proportion  to  its  size,  is  furnished  to  a  remark- 
able degree  with  blood.  The  largest  branch  of  the  creliac  artery 
runs  to  it  along  the  superior  margin  of  the  pancreas,  forming 
numerous  serpentine  flexures,  and  distinguished  for  its  thickness ; 
it  divides  into  several  trunks  for  penetrating  into  the  spleen,  and 
enters  by  the  foramina  in  the  fissure.  The  veins  come  out  by 
a  number  of  trunks  equal  to  what  the  artery  is  divided  into ; 
they  assemble  then  into  a  single  trunk,  which  attends  the  artery 
along  the  pancreas,  and  is  remarkable  for  the  tenuity  and  ex- 
tensibility of  its  coats.  The  splenic  vein  is  destitute  of  valves, 
and  empties  into  the  vena  portarum.  The  spleen  has  also  lym- 
phatic vessels;  and  is  furnished  with  nerves  from  the  solar 
plexus. 


64  ORGANS  OF  DIGESTION. 

Of  the  Intimate  Structure  of  the  Spleen. — The  Splenic  artery 
having  penetrated  into  this  organ,  is  divided  and  subdivided  into 
a  radiating  succession  of  very  fine  branches,  which,  according 
to  the  injections  of  Ruysch,  do  not  anastomose  with  each  other ; 
in  consequence  of  which,  one  part  is  sometimes  finely  injected 
and  ndt  another,  of  which,  in  my  own  observations,  1  have  had 
an  example.  The  veins,  on  the  contrary,  do  anastomose,  not 
only  as  regards  the  collateral  branches  of  the  same  primitive 
trunk,  but  also  by  the  collateral  branches  of  different  trunks. 
These  anastomoses  are  not  large.  The  arteries  terminate  freely 
in  the  veins,  as  may  be  proved  by  fine  injections,  and  by  the 
microscope. 

The  mass  of  the  spleen,  upon  superficial  examination,  seems 
to  consist  in  a  dark  brown  pulp,  which  is  contained  in  the  cells 
dividing  the  cavity  of  the  internal  coat,  and  may  be  easily  de- 
monstrated by  tearing  the  spleen,  and  scraping  it  with  a,  knife 
handle.  MM.  Assolont  and  Meckel  believe,  that  blood,  besides 
being  in  the  arteries  and  veins,  is  placed  in  a  state  of  particular 
combination  and  of  intimate  union  with  the  other  organic  ele- 
ments of  this  viscus,  and  with  a  large  quantity  of  albumen;  and 
that  this  combination  of  the  blood  forms  the  dark  brown  pulp 
alluded  to.  The  great  quantity  of  albumen  in  the  pulp,  is  rea- 
dily proved  oy  the  hard  coagulum  which  it  forms,  when  steeped 
in  alcohol.  But  a.  question  has  arisen  whether  the  pulp  be  ex- 
travasated  in  the  cells  which  contain  it,  or  whether  it  be  still  re- 
tained in  the  extremities  of  the  blood  vessels.  Superficial  exa- 
mination is  in  favour  of  the  first,  but  M.  Marjolin  denies  it  on 
the  following  grounds:  that  injections,  cautiously  made,  pass 
immediately  from  the  arteries  into  the  veins;  and  that  the 
spleen,  when  successfully  injected  and  "-frozen,  does  not  exhibit 
ice  in  the  interstices  of  its  vessels,  while  their  capillary  ramifi- 
cations, distended  by  the  injected  fluid,  are  distinctly  seen. 
From  these  he  concludes  that  the  glandular  structure  of  the 
spleen  is  formed  essentially  of  arterial  and  venous  capillary  ves- 
sels with  very  delicate  and  extensible  coats,  and  that  they  com- 
municate with  one  another  without  the  intermedium  of  any  cell; 
that  the  extreme  tenuity  of  these  vessels,  and  their  extensibility 
in  every  direction,  are  sufficient  to  explain  the  augmentation  of 


THE  SPLEEN.  65 

volume  of  the  spleen,  under  certain  circumstances,  as  well  as 
the  promptitude  of  its  diminution  under  others. 

In  addition  to  this  pulp,  many  observers  have  met  in  the 
spleen  with  an  abundance  of  rounded  corpuscles,  varying  in  size 
from  an  almost  imperceptible  magnitude  to  a  line  or  more  in  dia- 
meter.* They  are  of  a  gelatinous  consistence,  soft,  grayish,  and 
semi-transparent,  and  either  cluster  together,  or  are  widely  sepa- 
rated. By  Malpighi,  they  were  considered  glandular,  and,  by 
Ruysch,t  as  convoluted  vessels.  Professor  Scemmering,  from  the 
following  paragraph,  seems  to  join  in  the  opinion  of  the  latter: 
"  Qui  nonnunquam  occurrunt,  acini  vel  glomeruli,  microscopii 
ope  accuratissime  explorati  nihil  sunt,  nisi  vasorum  fasciculi,  vel 
teretes  penicilli  aut  cirri  vasculosi."  According  to  the  observa- 
tions of  Sir  Everard  Home,  they  swell  considerably  after  an  ani- 
mal has  finished  drinking. 

The  spleen,  from  having  no  excretory  duct,  and,  consequently, 
from  our  inability  to  ascertain  whether  it  secretes,  has  its  nature 
and  uses  shrouded  in  mystery.  No  single  theory  concerning  it 
has  ever  been  generally  adopted,  for  speculations  have  multiplied 
in  proportion  to  the  obscurity  of  the  subject.  The  idea,  howe- 
ver, on  the  use  of  this  body,  which  to  me  is  most  reasonable,  is, 
that  it  acts  a  subsidiary  part  to  the  liver.  It  would  seem,  indeed, 
as  a  general  rule  in  regard  to  glandular  structures  and  such  other 
highly  vascular  organs  of  the  body  as  have  an  intermittent  func- 
tion, that  the  blood  which  is  sent  to  them  during  their  state  of 
activity,  should  be  passed  off  through  a  different  channel,  while 
they  are  in  a  state  of  repose.  This  does  a  double  service,  it  pre- 
vents superfluous  secretions,  and  it  also  keeps  up  the  vascular 
equilibrium  of  the  body,  as  there  must  be  always  in  readiness  a 
quantity  of  blood  sufficient  for  the  supply  of  any  secretion  which 
may  be  wanted  for  the  time. 

This  proposition  will  derive  some  additional  illustrations  from 
the  fetal  state.  The  kidneys  being  then  inactive  the  glandula? 
renales  take  off  their  blood,  and  thereby  prevent  what  would 
otherwise  be  a  very  inconvenient  secretion  of  urine ;  again,  the 
lungs  being  also  then  inactive,  the  circulation  through  them  is 
proportionately  reduced,  and  the  superabundant  blood  is  con- 

*  Malpighi,  Ruysch,  Hewson,  Home,  Dupuytren,  Meckel,  8cc. 
f  Epist.  Anat.  IV. 


66  ORGANS  OF  DIGESTION. 

ducted  through  the  thymus  gland.  But  as  the  full  functions  of 
the  lungs  and  of  the  kidneys  are  established  upon  birth,  and  con- 
tinue uninterrupted  during  life,  their  supplementary  organs,  the 
thymus  gland,  and  the  capsulae  renales,  are  not  wanted,  and  they 
wither  away  after  the  early  period  of  infantile  existence  is  passed. 

In  regard  to  the  liver,  its  functions  also  suspended  during  the 
fetal  state,  are  of  an  intermittent  kind  throughout  life,  the  spleen 
may,  therefore,  be  considered  a  vicarious  organ  for  it  during  the 
whole  period  of  existence,  receiving  its  blood  during  the  continu- 
ation of  uterine  life,  and,  in  the  intermission  of  action,  during 
common  life.  The  spleen  is,  therefore,  an  organ  useful  to  the 
foetal  and  to  the  perfect  state,  and  we,  consequently,  never  see 
it  in  the  collapsed  and  dwindled  condition  of  the  thymus  gland, 
and  renal  capsule. 

The  same  reasoning  which  applies  to  the  spleen  will  also  ap- 
ply to  the  Thyroid  Gland,  for  the  latter  may  be  considered  as  ex- 
ecuting for  the  salivary  glands  during  foetal  and  perfect  existence, 
what  the  spleen  does  for  the  liver.  For  it  is  ascertained,  that 
the  salivary  glands  are  inactive  during  foetal  existence,  have  only 
an  intermittent  action  during  perfect  life,  and,  therefore,  proba- 
bly stand  in  need  of  a  supplementary  organ  during  their  periods 
of  inactivity. 

SECT.  III. — OF  THE  PANCREAS. 

The  Pancreas  (Pancreas]  secretes  saliva,  and  is  the  largest  of 
the  salivary  glands.  It  is  fixed  in  the  lower  back  part  of  the  epi- 
gastric region ;  and  extends  horizontally  across  the  spine,  being 
separated  from  it  by  the  lesser  muscle  of  the  diaphragm.  It  is 
connected  to  the  spleen  on  the  left;  at  its  right  extremity  is  sur- 
rounded by  the  curvature  of  the  duodenum ;  is  bounded  in  front 
by  the  stomach,  which  conceals  it ;  and  is  placed  between  two 
laminae  of  the  mesocolon. 

The  pancreas  is  about  six  or  seven  inches  long,  two  wide,  and 
flattened  before  and  behind.  Its  figure  would  be  represented  by 
a  parallelogram,  were  it  not  that  its  right  extremity  is  enlarged 
considerably  into  a  head  or  tuber,  to  which  Winslow  gave  the 
n'ame  of  the  Lesser  Pancreas.  The  anterior  face  of  this  organ  is 
turned  obliquely  upwards,  and  is  covered  by  the  superior  lamina 


THE  PANCREAS.  67 

of  the  mesocolon.  The  posterior  face  looks  obliquely  downwards, 
and  is  in  contact  with  the  aorta,  the  vena  cava  ascendens,  the 
superior  mesenteric  vessels,  and  several  nerves :  along  the  supe- 
rior margin  of  this  face  exists  a  long  superficial  fossa,  occupied 
by  the  splenic  artery  and  vein. 

With  the  exception  of  the  loose  covering  given  by  the  mesoco- 
lon, the  pancreas  has  no  peritoneal  coat;  neither  has  it  an 
appropriate  tunic,  unless  we  consider  as  such  the  lamina  of  con- 
densed cellular  membrane  which  envelops  it,  and  sends  in  pro- 
cesses between  its  lobules,  as  in  the  case  of  the  salivary  glands  in 
the  neck. 

Of  the  Minute  Structure  of  the  Pancreas. — This  body,  like  the 
other  glands,  which  discharge  saliva,  is  of  a  light  gray  or  pink 
colour.  It  consists  in  lobules  of  various  forms  and  sizes,  united 
by  an  intermediate  cellular  tissue,  and  having  their  interstices  oc- 
cupied by  numerous  blood  vessels.  These  lobules,  by  a  slight 
maceration,  may  be  separated  and  resolved  into  small  granular 
masses,  constituting  integral  portions  of  the  gland. 

The  arteries  of  the  pancreas  come  principally  from  the  splenic, 
as  it  cruises  along  the  superior  margin.  The  veins  empty  into 
the  splenic,  and  thus,  finally,  into  the  vena  portarum.  It  is  fur- 
nished with  nerves  from  the  solar  plexus,  and  has  lymphatics. 

The  excretory  duct  of  this  gland  (Ductus  Wirsungii)  arises,  by 
very  fine  roots  or  tubes,  from  each  of  the  small  granular  masses. 
These  tubes  coalesce  into  larger  ones,  which  run  transversely 
from  the  periphery  towards  the  centre  of  the  gland,  inclining 
slightly,  at  the  same  time,  towards  the  right.  These  secondary 
tubes  finally  discharge  successively  into  a  single  one,  which  runs 
the  whole  length  of  the  gland  nearly  in  its  middle.  The  single 
tube,  by  these  additions,  enlarges  continually  from  left  to  right, 
being  small  where  it  begins  at  the  splenic  extremity  of  the  pan- 
creas, and  about  the  size  of  a  crow-quill  at  the  duodenal.  At  the 
latter  place,  it  is  joined  by  the  duct  of  the  lesser  pancreas,  which 
is  derived  after  the  same  rule  as  itself.  The  pancreatic  duct,  al- 
most immediately  afterwards,  empties  into  the  ductus  communis 
choledochus,  or  runs  at  the  side  of  the  latter,  and  makes  a  dis- 
tinct opening- near  it  into  the  duodenum,  at  the  posterior  part  of 
the  second  curvature. 


BOOK  V. 


OF  THE  URINARY  ORGANS. 

THE  Urinary  Organs,  (Organa  Uropoietica^  being  destined 
to  secrete  and  convey  the  urine  out  of  the  body,  consist  in  the 
Kidneys,  the  Renal  Capsules,  the  Ureters,  the  Bladder  and  the 
Urethra. 


Of  the  Kidneys. 

The  Kidneys  (Renes]  are  two  glandular  bodies  for  the  secre- 
tion of  the  urine,  fixed  one  on  either  side  of  the  spine.  They 
are  in  the  back  part  of  the  lumbar  regions,  have  their  internal 
edges  inclining  very  slightly  forwards,  and  extend  from  the 
upper  margin  of  the  eleventh  dorsal  to  the  lower  margin  of  the 
second  lumbar  vertebra;  the  right,  however,  is  ten  or  twelve 
lines  lower  than  the  left,  owing  to  the  thick  posterior  margin 
okthe  right  lobe  of  the  liver,  which  presses  it  downwards.  The 
kidneys  are  covered  in  front  by  the  peritoneum  and  the  lumbar 
portions  of  the  large  intestine,  but  in  such  a  manner  as  to  be 
separated  from  them,  in  corpulent  subjects,  by  a  surrounding 
layer  of  fat;  behind,  they  repose  upon  the  lower  part  of  the 
great  muscle  of  the  diaphragm,  upon  the  quadrati  lumborum, 
and  upon  the  upper  end  of  the  psose  magni  muscles. 

The  kidney  is  a  hard  solid  body,  of  a  brown  colour;  in  shape 

it  is  a  compressed  ovoid,  excavated  on  the  margin  which  it 

presents  to  the  spine,  and  bears  a  very  strong  resemblance  to 

the  common  kidney  bean.     Its  flat  surfaces  present  forwards 

VoL.IL— 10 


70  URINARY  ORGANS. 

and  backwards,  and  the  broad  end  of  the  ovoid  is  above.  Its 
periphery  is  smooth,  so  that  one  does  not  see  from  an  external 
examination  the  lobules  or  internal  divisions.  The  excavation 
of  the  kidney,  called  its  fissure,  (hiium  renale)  occupies  about 
one-third  of  its  long  diameter,  is  bevelled  in  front,  and  leads  to 
the  very  interior  of  the  gland;  conducting  its  blood  vessels  and 
excretory  duct,  which  have  to  pass  through  a  quantity  of  cellular 
and  adipose  matter.  The  kidneys  are  generally  of  equal  size, 
being  about  four  inches  long,  and  two  wide;  and  each  one  weighs 
three  or  four  ounces.  They  have  no  ligaments  for  keeping 
them  in  position,  but  depend  for  the  latter  upon  the  adjacent 
cellular  "adhesions  and  blood  vessels. 

The  kidney  being  destitute  of  a  peritoneal  coat,  has  a  well 
marked  capsule  which  envelops  it  entirely  and  penetrates  into 
its  fissure  for  some  depth,  where  it  is  perforated  with  foramina 
for  transmitting  the  blood  vessels  and  the  ureter.  This  capsule 
is  white,  semi-transparent,  fibrous,  strong,  and  elastic:  it  adheres 
to  the  surface  of  the  kidney  by  delicate  cellular  and  vascular 
filaments,  which  are  so  weak  that  they  permit  it  to  be  stripped 
off  without  difficulty,  and  when  so  removed,  some  indications 
of  the  original  lobulated  condition  of  the  organ  are  seen. 

The  kidney  receives  from  the  aorta  one  or  more  branches, 
called  the  renal  or  emulgent  arteries,  which  divide  as  they  ap- 
proach the  fissure;  and  having  got  into  the  substance  of  the 
gland  are  distributed  by  innumerable  twigs  to  all  parts  of  it. 
Some  terminate  in  veins,  others  in  the  substance  of  the  organ, 
and  others,  again,  in  the  excretory  tubes.  The  veins  equal  in 
number  the  arteries,  and  are  somewhat  larger.  When  both, or 
even  one,  of  these  systems  of  blood  vessels  is  injected  with 
wax  and  corroded,  its  branches  are  so  abundant  as  to  retain  the 
form  of  the  gland.  In  engaging  in  the  fissure  of  the  kidney, 
the  arterial  ramifications  are  in  front,  the  veins  in  the  middle, 
and  the  commencement  of  the  ureter  behind.*  The  artery  on 
the  right  side  is  longer  than  that  on  the  left.  The  reverse  is 
the  case  with  the  emulgent  veins,  as  they  empty  into  the  vena 
cava  ascendens.  This  arrangement  is  owing  to  the  relative 

*  This  rule  is  subject  to  frequent  variations, 


THE  KIDNEYS.  7l 

position  of  the  aorta  and  the  vena  cava  ascendens,  as  the  first  is 
on  the  left  side  of  the  spine,  and  the  last  on  the  right  side. 

The  nerves  come  from  the  solar  plexus  of  the  sympathetic, 
and  adhering  to  the  arteries  cannot  be  traced  very  far  through 
the  glandular  structure.  The  quantity  of  lymphatics  is  consi- 
derable. 

Of  the,  Minute.  Structure  of  the  Kidney. — When  the  kidney 
is  cut  open  longitudinally,  it  obviously  consists  of  two  kinds  of 
substance,  differing  in  their  situations,  colour,  consistence  and 
texture.  The  one  nearest  to  the  periphery  of  the  gland  is  called 
from  its  position  Cortical,  (Subslantia  Corticalis,  Glandulosa,) 
while  the  other,  being  more  internal,  is  designated  as  the  Me- 
dullary or  Tubular,  (Substantia  Medullaris;  Tubulosa;  Fi- 
brosa.) 

The  Cortical  or  Secretory  Substance  forms  the  whole  circum- 
ference of  the  kidney,  and,  on  an  average,  is  about  two  lines  in 
thickness:  but  it  is  thicker  at  some  points;  as  from  its  internal 
face  processes  converge  towards  the  centre  of  the  gland,  which 
separate  the  tubular  part  into  as  many  distinct  portions  of  a 
conoidal  shape.  It  is  composed  principally  of  arteries  and  veins 
ramifying,  among  small  graniform  corpuscles  that  secrete  the 
urine,  and  are  very  distinct  when  viewed  with  a  microscope. 
It  tears  with  facility,  thereby  presenting  this  granular  appearance, 
and  is  of  a  dark,  or  reddish  brown  colour,  varying  considerably, 
however,  according  to  the  cause  of  death. 

The  granular  corpuscles  which  form  the  mass  of  the  cortical 
or  secretory  substance,  are,  individually,  imperfectly  visible  to 
the  naked  eye,  and  appear  like  rounded  points. 

The  celebrated  Ruysch,  who  was  distinguished  for  the  suc- 
cess of  his  injections,  and  for  the  acuteness  of  his  vision,  de- 
clared that  they  consisted  wholly  in  the  very  fine  extremities 
of  arteries  and  veins  having  a  penicillous  arrangement;  while 
Malpighi  and  Schumlansky  viewed  them  as  purses  or  small 
sacs  of  a  glandular  character,  specifically  suited  to  secrete  urine, 
and  upon  whose  parietes  the  blood  vessels  ramified.  From 
these  granuli  or  acini  the  incipient  extremities  of  the  tubuli 
uriniferi  take  their  rise. 


72  URINARY  ORGANS. 

The  Tubular  or  Conoidal  portion,  consists  in  from  twelve  to 
eighteen  conoidal  fasciculi  (Pyramided  MalpighiancE}  present- 
ing their  rounded  bases  towards  the  cortical  matter,  and  en- 
closed in  it,  while  their  apices  converge  to  the  central  cavity  of 
the  kidney,  the  surface  of  which  they  form.  The  bodies  of 
these  pyramids,  as  just  mentioned,  are  separated  by  processes 
of  the  cortical  matter;  but  their  apices  are  free,  and  project  from 
the  internal  surface  of  the  kidney  so  as  to  resemble  as  many 
small  nipples,  whence  they  are  called  Papillas  Renales.  Fre- 
quently two  of  the  pyramids  coalesce  so  as  to  form  but  one 
papilla  together;  in  such  case  the  latter  generally  preserves  a 
duplicate  appearance.  The  papillae  are  arranged  into  three  ver- 
tical rows,  one  before,  one  in  the  middle,  and  another  behind; 
those  of  the  foremost  row  are  turned  backwards;  those  of  the 
middle  look  inwards;  and  those  behind  look  forwards.  Not  un- 
frequently  there  is  a  small  depression  (foveola]  on  the  very 
summit  of  the  papilla.  The  tubular  part  is  of  a  lighter  colour 
and  harder  than  the  cortical,  but  the  difference  in  these  respects 
is  not  always  manifest. 

The  conoidal  fasciculi  may  each  be  considered,  along  with  its 
appertaining  cortex,  as  a  sort  of  distinct  gland,  or  at  least  as  a 
lobe;  for  upon  them  depend  the  lobulated  appearance  of  the 
kidneys  of  a  foetus,  and  of  animals.  Each  cone,  when  analyzed, 
is  found  to  consist  in  a  collection  of  tubes  (Due/us  Urinifm 
Bellini]  converging  from  the  circumference  of  the  kidney  to 
the  apex  of  the  papilla.  These  tubes  are  more  numerous  near 
the  base,  in  consequence  of  their  successive  junction  in  approach- 
ing the  apex:*  their  terminating  orifices,  on  the  latter,  appear 
like  small  pores,  from  which  the  urine  can  be  squeezed  in  little 
drops. 

In  the  early  part  of  the  course  of  the  ductus  uriniferi,  while 
they  are  still  in  the  cortical  matter,  they  are  wound  up  in  a 
very  serpentine  and  tortuous  manner,  and  are  distinguished  by 
the  name  of  Cortical  Canals,  (Ductus  Ferrenii.^)  They  com- 
monly go  alone,  winding  their  way  in  the  cortical  substance 
until  they  reach  its  most  interior  face;  they  then  become  straight, 


Schumlansky,  Dis.  de  Struct.  Renum,  Strasburg,  1788. 

A.  Ferrein;  sur  la  Structure  des  reins  et  du  foie,    Mem.  de  Paris,  1749. 


THE  KIDNEYS.  73 

form  the  medullary  substance,  and  have  the  name  of  the  con- 
duits of  Bellini.* 

Some  of  the  calculations  on  this  subject  are  not  a  little  curious. 
It  was  ascertained  by  Ferrein  that  in  each  of  the  conoidal  fas- 
ciculi (Pyramides  Malpighianse)  there  were,  at  least  seven  hun- 
dred subordinate  cones  or  pyramids;  and  as  the  number  of  co- 
noidal fasciculi  is  generally  about  fifteen,  these  pyramids  would 
amount  to  ten  thousand  five  hundred.  Again,  each  of  the  sub- 
ordinate pyramids  (Pyramides  Ferrenii)  is  composed  of  many 
hundred  uriniferous  tubes,  and,  by  the  observations  of  Eysen- 
hardt,|  each  of  these  tubes  consist  of  twenty  smaller  ones. 

The  arteries  of  the  kidneys,  in  ramifying  minutely  through 
its  structure,  adopt  the  following  arrangement.     They  first  of 
all  pass  through  the  processes  sent  inwards  from  the  cortical 
matter  between  the  Pyramids  of  Malpighi,  or  large  cones,  and, 
having  got  into  the  cortical  matter,  they  divide  into  very  fine 
twigs,  which  form  arcades  around  the  bases  of  the  pyramids 
of  Ferrein,  and  pass  between  them.J     These  arcades  have  but 
few  anastomoses  with  each  other,  and  their  branches  go  almost 
exclusively  to  the  cortical  substance,  very  few  of  them  being 
found  on  the  tubular.     Their  branches  radiate  from  the  con- 
vexities of  the  arches  so  as  to  surround  the  base  of  each  cone, 
and  to  penetrate  to  the  surface  of  the  kidney.      Some  of  these 
branches  terminate  in  corresponding  veins,  and  others  on  the 
granular  corpuscles,  or  acini.     The  connexion  between  the  cor- 
puscles and  the  arteries,  has  been  compared  to  that  between 
grapes  and  the  stems  on  which  they  grow,  so  as  to  form  a  bunch. 
The  veins  penetrate  the  substance  of  the  kidney,  and  have  a 
similar  distribution;  but  they  are  much  larger  than  the  arteries, 
and  have  free,  large  and  numerous  anastomoses.     A  connexion 
of  the  corpuscles  with  the  veins  is  not  quite  evident,  and,  even 
if  it  does  exist,  remains  yet  to  be  proved;  at  least,  in  the  opinion 
of  some  anatomists:  the  fact,  however,  is  well  established,  that 
fine  injections  will  readily  pass  from  the  veins  into  the  tubuli 
uriniferi. 

In  one  instance,  I  found  in  a  young  female  subject  one  of  the 

*  L.  Bellini,  de  Structure  Renum.  Florence,  1662. 

f  De  Struct.  Renum.  Obs.  Micros.  Berlin,  1818.  t  Schumlansky. 


74  URINARY  ORGANS. 

kidneys  in  the  pelvis  in  front  of  the  rectum.  A  similar  case 
has  been  seen  by  Professor  Hensinger;*  and  I  have  met  with 
several  instances  of  a  coalition  across  the  spine,  of  the  two 
kidneys,  so  as  to  present  the  appearance  of  a  bilobed  organ. 

Of  the  Excretory  Duct  of  the  Kidney,  or  the  Ureter. 

The  Ureter  is  a  canal  which  conveys  the  urine  from  the  kid- 
ney to  the  bladder.  It  commences  in  the  centre  of  the  kidney 
by  an  enlargement  called  pelvis,  which  branches  off  into  three 
or  four  portions,  (calices}  one  above,  one  below,  and  one  or  two 
intermediate.  Each  of  these  calices  is  divided,  at  its  free  ex- 
tremity, into  three  or  four  short  funnel-shaped  terminations, 
(Infundibula.)  Each  of  these  terminations  embraces  by  its 
expanded  orifice,  the  base  of  a  papilla,  so  as  to  permit  the  latter 
to  project  into  it,  and  thereby  to  distil  its  urine  there.  Very 
frequently  the  number  of  papillae  exceeds  that  of  the  infundi- 
bula,  in  which  case  two  of  the  former  project  into  one  of  the 
latter. 

The  pelvis  of  the  kidney  having  emerged  at  the  fissure  be- 
hind the  vessels,  from  being  expanded  and  somewhat  conoidal 
in  shape  is  reduced  to  a  cylindrical  canal,  which,  properly 
speaking,  is  the  ureter:  the  latter  is  about  the  size  of  a  goose- 
quill  and  descends  through  the  lumbar  region,  between  the  pe- 
ritoneum, and  the  psoas  magnus  muscle.  It  dips  into  the  pelvis 
by  crossing  in  front  of  the  primitive  iliac  vessels  and  the  in- 
ternal iliac,  crosses  the  vas  deferens  at  the  back  of  the  bladder, 
and  penetrating  obliquely  the  coats  of  the  latter,  terminates  in 
an  orifice  ten  or  twelve  lines  behind  that  of  the  neck  of  the 
bladder. 

The  excretory  duct  of  the  kidney  is  formed  by  two  coats. 
The  external  is  a  condensed,  fibrous,  and  cellular  tissue,  but  is 
destitute  of  any  thing  like  muscle.  The  internal  is  a  thin  mu- 
cous lamina,  which  can  be  raised  up  without  much  difficulty, 
and  is  continuous,  at  its  lower  end,  with  the  internal  coat  of  the 
bladder;  at  the  upper  end,  it  is  supposed  by  some  anatomists  to 
be  reflected  over  the  papilla?,  and  even  to  pass  for  some  distance 

*  Am.  Med.  Jour.  Vol.  iii.  p.  442. 


THE  KIDNEYS.  75 

into  the  tubuli  uriniferi.  This  duct  has  considerable  powers  of 
extension,  as  manifested  by  its  transmitting  large  calculi  from 
the  kidney,  and  also,  by  its  general  enlargement  in  some  cases 
of  obstructed  urethra;  its  sensibility  is  exquisite  when  irritated 
by  a  calculus  passing  down  it. 

Of  the  Renal  Capsules. 

The  Renal  Capsules  (Capsulae  Renales,  Penes  Succentu- 
riatij)  are  two  small  bodies,  one  on  either  side,  placed  upon 
the  upper  end  of  the  kidney.  They 'are  of  a  yellowish  brown 
colour  tinged  with  red,  have  no  excretory  ducts,  and  are  more 
distinctly  developed  and  softer  in  the  perfect  foetus  than  in  the 
adult;  whence  they  are  ranked  among  those  organs,  as  the  thy- 
mus  gland,  and  others;  which,  having  some  peculiar  value  in 
fcetal  existence,  are  perhaps  unnecessary  to  that  of  the  adult.* 
They  are  of  a  triangular  pyramidal  shape,  flattened  before  and 
behind,  and  rest  by  a  concave  base  upon  the  kidney;  they  are 
about  fifteen  lines  high  and  as  many  wide. 

They  are  surrounded  by  a  proper  coat  of  lamellated  con- 
densed cellular  tissue,  which,  by  detaching  inwards  its  prolon- 
gations, keeps  the  parts  of  these  bodies  together,  and  marks  out 
their  divisions.  In  the  centre  of  the  renal  capsule,  a  cavity 
may,  from  time  to  time,  be  found;  but,  according  to  my  own 
observations,  nothing  is  less  certain  than  its  existence;  and,  in 
the  opinion  of  Meckel,  when  found,  it  is  the  result  of  cadaverous 
decomposition.  In  the  foetus  it  contains  a  reddish  viscid  fluid, 
which  seems  to  consist  in  a  large  share  of  albumen,  as  it  coagu- 
lates with  alcohol;  in  children,  this  fluid  becomes  yellow;  in 
adults  it  is  dark  brown;  and  in  old  people  it  is  either  entirely 
deficient,  or  in  a  remarkably  small  quantity. 

Of  the  Minute  Structure  of  the  Capsulae  Renales. — The 
arteries  of  these  bodies  come  from  the  emulgents,  from  the 
phrenics,  and  from  the  aorta.  The  veins  of  the  right  one  ter- 
minate in  the  cava  ascendens,  and  of  the  left  in  the  emulgent. 
Each  one  is  divisible  into  lobes,  and  by  a  slight  maceration 

*  This  opinion  has  recently  been  confirmed  in  a  dissection  of  a  foetus,  where 
1  found  the  capsulx  renales,  though  the  kidneys  were  absent. 


76  URINARY  ORGANS. 

may  be  reduced  into  lobules  and  small  granulations.  The  ex- 
ternal part  is  rather  more  consistent  and  yellow  than  the  in- 
ternal. The  granulations  seem  to  have  an  intimate  connexion 
with  the  veins,  as  they  are  easily  penetrated  by  fluid  injections 
from  the  latter. 

Reputed  excretory  ducts  for  these  bodies  have  been  found 
going  to  the  testicles,  to  the  pelvis  of  the  kidneys,  and  to  the 
thoracic  duct,  but  no  weight  is  now  attached  to  such  assertions. 

Of  the.  Bladder. 

The  Bladder  ( Tesica  Urinaria,)  is  the  reservoir  for  the  urine, 
and  is  placed  in  the  pelvis,  just  behind  the  symphysis  of  the 
pubes.  When  pressed  upon,  as  it  commonly  is,  by  the  ad- 
jacent viscera,  it  is  flattened  somewhat  before  and  behind;  but 
removed  from  the  body  and  inflated,  it  is  an  elongated  sphere 
or  an  oval;  the  greatest  diameter  of  which  is  vertical,  in  regard 
to  the  linea  ileo-pectinea.  The  superior  end  of  the  bladder  is 
called  the  upper  fundus,  and  the  lower  end  the  inferior  fundus; 
the  latter  is  rather  more  obtuse  than  the  other;  and  between 
the  two  is  the  body.  The  neck  of  the  bladder  is  its  place  of 
junction  with  the  urethra.  The  form  of  the  bladder  is  influ- 
enced by  age  and  by  sex;  in  very  young  infants  it  is  cylindroid, 
and  owing  to  the  smallness  of  the  pelvis,  rises  up  almost  wholly 
into  the  abdomen.  In  the  adult  woman,  who  has  frequently 
borne  children,  it  is  nearly  spherical,  has  its  greatest  diameter 
transverse,*  and  is  more  capacious  than  in  man. 

The  bladder  is  bounded  in  front  by  the  pubes,  above  by  the 
small  intestine,  behind  by  the  rectum,  and  below  by  the  pro- 
state gland  and  the  vesiculae  seminales.  From  its  superior  end 
there  proceeds  to  the  umbilicus  a  long  conical  ligament,  the 
urachus,  which  is  placed  between  the  linea  alba  and  the  perito- 
neum, and  produces  a  slight  elevation  or  doubling  of  the  latter. 
In  mankind,  the  urachus  is  solid:  some  very  rare  cases,  how- 
ever, are  reported,  in  which  it  has  been  hollow,  so  as  to  permit 
the  urine  to  flow  through  it  from  the  bladder.  This  vicious 
conformation  has  generally  been  attended  with  a  congenital  ob- 
struction of  the  urethra.!  When  the  anterior  parietes  of  the  ab- 

*  H.  Cloquet,  Anat.  Descrip.  f  Sabatier,  Anat.  vol.  iii.  p.  19. 


THE  BLADDER.  77 

domen  are  put  upon  the  stretch;  a  semi-lunar  fold  of  the  peri- 
toneum, as  formerly  mentioned,  is  seen  to  proceed,  on  either 
side  of  the  urachus,  from  the  lateral  surface  of  the  bladder  al- 
most to  the  umbilicus.  These  folds  contain,  in  their  loose  edge, 
the  fibrous  remains  of  the  umbilical  arteries  of  the  foetus,  called, 
subsequently  to  uterine  life,  the  Round  Ligaments  of  the  blad- 
der, though  they  have  little  or  no  influence  on  its  position. 
The  bladder  is  also  fixed  in  its  situation  by  the  pelvic  aponeu- 
rosis,  a  membrane  elsewhere  described  with  the  organs  of  ge- 
neration. , 

The  bladder  consists  of  four  coats:  the  Peritoneal,  the  Mus- 
cular, the  Cellular,  and  the  Mucous. 

The  Peritoneal  Coat  is  very  imperfect,  and  is  derived  from 
the  part  of  the  peritoneum  which  descends  from  the  anterior 
parietes  of  the  abdomen  into  the  pelvis.  It  covers  the  upper 
and  the  posterior  face  of  the  bladder,  and  then  passes  to  the 
rectum,  by  sinking  down  between  these  two  organs,  so  as  to 
form  the  small  pouch  beneath  the  lower  fund  us  of  the  bladder; 
the  apex  of  this  pouch  reaches  within  an  inch  of  the  base  of  the 
prostate.  The  upper  margin  of  this  pouch  next  to  the  bladder, 
forms  a  strong  horizontal  doubling,  stretching  across  the  pelvis, 
when  the  rectum  is  empty,  and  is  on  a  level  with  the  posterior 
end  of  the  vesiculse  seminales.  Being  connected  to  the  subja- 
cent muscular  coat  by  a  thin  lamina  of  loose  cellular  membrane, 
the  peritoneum  may  be  dissected  off  without  difficulty.  In  con- 
siderable distentions  of  the  bladder,  it  is  reflected  from  the  up- 
per end  of  the  latter  to  the  abdominal  muscles  in  a  line  much 
above  the  pubes;  whereby  a  good  opportunity  is  afforded  of 
reaching,  with  an  instrument,  the  cavity  of  the  bladder  without 
injuring  the  peritoneum. 

The  Muscular  Coat  is  of  a  thickness  intermediate  to  thatof 
the  stomach  and  of  the  oesophagus,  and  its  fibres  are  pale. 
They  pass  in  very  varied  directions,*  and  are  collected  into 
flattened  fasciculi,  leaving  interstices  between  them,  through 
which  the  internal  coat  is  occasionally  caused  to  protrude,  in 
.strictures  and  other  obstructions  of  the  urethra.  These  fasci- 

*  Santorini,  Septemd.  Tabul. 
VOL.  II.— 11 


7S  URINARY  ORGANS. 

culi,  for  the  most,  part,  arise  about  the  neck  of  the  bladder,  and 
ascending  upwards,  before,  behind,  and  laterally,  terminate  at 
the  superior  fundus  in  the  base  of  the  urachus.  Within  these, 
which  may  be  considered  as  the  longitudinal  fibres  of  the  blad- 
der, there  are  others  forming  a  thinner  lamina,  whose  course  is 
transverse,  or  oblique:  they  serve  to  connect  the  preceding. 
As  the  muscular  fibres  are  collected  at  the  neck  of  the  bladder, 
and  at  the  urachus,  there  is,  of  course,  an  increased  thickness  at 
these  points. 

The  Cellular  Coat  consists  in  a^  close,  dense,  lamellated,  and 
filamentous  tissue,  very  extensible  and  difficult  to  tear.  It  is 
impervious  to  water,  adheres  closely  to  the  muscular  coat  with- 
out, and  to  the  mucous  within,  so  as  to  form  a  strong  bond  of 
union  between  them.  It  is  pervaded  by  many  vessels  and 
nerves,  which  it  conveys  to  the  mucous  coat. 

The  Mucous  Coat  is  also  called  the  villous,  but  is  much  more 
smooth  than  the  corresponding  one  of  the  stomach.  It  is  white, 
with  a  slight  tinge  of  red,  and  abounds  with  mucous  follicles, 
which,  though  small  and  scarcely  discernible  in  a  natural  state, 
are  rendered  very  obvious  by  disease.  It  stretches  with  much 
facility,  but,  like  other  mucous  membranes,  does  not  restore 
itself  readily,  and  is  rather  thrown,  in  the  contracted  state  of 
the  bladder,  into  wrinkles  or  folds,  having  a  diversified  course, 
and  of  a  fugitive  character,  as  they  disappear,  again  upon  the 
next  distention.  It  is  very  vascular. 

The  internal  face  of  this  coat  presents,  at  its  inferior  part,  the 
following  appearances: 

1.  TheVesical  Triangle  ( Trigonus  Lieutaudi,  Trigone  Ve- 
sicale)  is  placed  immediately  behind  and  below  the  neck  of  the 
bladder,  occupying  the  space  between  it  and  the  orifices  of  the 
ureters.     It  is  an  equilateral  triangle  of  an  inch  in  length,  its 
surface  is  smooth,  is  not  affected  materially  in  extent  either  by 
the  dilatation  or  the  contraction  of  the  bladder,  and  is  elevated 
so  as  to  be  sufficiently  distinct  and  well  defined. 

2.  The  anterior  angle  of  the  triangle  looks  into  the  orifice  of 
the  urethra,  and  is  generally  so  elevated  that  it  has  obtained 
the  name  of  Uvula  Vesicse;  it  is,  however,  simply  a  projection 


THE  BLADDER.  79 

of  the  mucous  membrane  depending  upon  the  subjacent  third 
lobe  of  the  prostate;  which,  at  this  point,  is  not  unfrequently 
much  enlarged  in  the  aged,  and  then  presents  a  great  difficulty 
in  the  introduction  of  a  catheter. 

3.  Tlje  Orifices  of  the  ureters  form  the  posterior  angles  of  the 
triangle,  and  are  contracted  somewhat  below  the  size  of  Ihe  ca- 
nals themselves.     They  are  said,  by  Mr.  Charles  Bell,*  to  be 
furnished  each  one  with  a  small  fasciculus  of  muscular  fibres, 
which  runs  backwards  from  the  orifice  of  the  urethra,  just  be- 
neath the  lateral  margins  of  the  triangle,  and,  in  its  contraction, 
will  stretch  the  orifice  of  the  ureter  so  as  to  permit  an  easy  pas- 
sage of  the  urine  into  the  bladder.     The  retrogradation  of  the 
urine  is  prevented  by  the  ureter  passing  obliquely,  for  six  or 
eight  lines,  between  the  muscular  and  mucous  coat;  there  is 
something  also  in  the  obliquity  of  the  orifice  itself  which  as- 
sists in  this  effect;  as  I  have  ascertained  by  removing  the  mus- 
cular coat  entirely,  at  this  point,  and  dissecting  up  the  ureter, 
notwithstanding  which,  the  bladder,  when  inflated,  still  retained 
its  contents.     Where  the  ureter  penetrates  the  muscular  coat,  I 
have  in  several  instances  found  a  layer  of  longitudinal  muscular 
fibres  enveloping  it  for  half  an  inch,  or  an  inch. 

4.  The  Inferior  Fundus  of  the  bladder  (bas-fond  of  the  French) 
is  a  depression  of  the  general  concavity  of  the  bladder,  of  about 
six  lines  in  depth,  placed  between  the  base  of  the  triangle  and 
the  posterior  side  of  the  bladder.     In  the  erect  position,  calcu- 
lus, when  one  has  it,  lodges  there. 

5.  The  Internal  Orifice  of  the  neck  of  the  bladder  resembles 
strongly  that  of  a  Florence  flask,  modified,  however,  by  the 
projection  of  the  uvula  vesicse,  which  makes  is  somewhat  cres- 
centic  below.     The  neck  of  the  bladder  penetrates  the  prostate 
gland,  but,  at  its  commencement,  is  surrounded  by  loose  cellu- 
lar tissue  containing  a  very  large  and  abundant  plexus  of  veins.t 
The  internal  layer  of  muscular  fibres  is  here  .transverse;  and 
they  cross  and  intermix  with  each  other  in  different  direction's, 

*  Med.  Chir.  Trans.     Vol.  iii. 

f  Mascagni,  Anat.  Univ.  Str.  Prim.  Tab.  Spec.  Fig.  V. 


80  URINARY  ORGANS. 

forming  a  close  compact  tissue,  which  has  the  effect  of  a  parti- 
cular apparatus  for  retaining  the  urine,  and  is  called  Muscu- 
lus  Sphincter  Vesicae  Urinarise.  Generally,  anatomists  have 
not  considered  this  structure  as  distinct  from  the  muscular  coat 
at  large;  but  Mr.  Charles  Bell,  of  London,  whose  reputation  as 
an  anatomist  is  well  established,  gives  the  following  account  of 
it:— 

"Begin  the  dissection  by  taking  off  the  inner  membrane  of 
the  bladder  from  around  the  orifice  of  the  urethra.  A  set  of 
fibres  will  be  discovered  on  the  lower  half  of  the  orifice,  which, 
being  carefully  dissected,  will  be  found  to  run  in  a  semicircular 
form  round  the  urethra.  These  fibres  make  a  band  of  about 
half  an  inch  in  breadth,  particularly  strong  on  the  lower  part 
of  the  opening,  and,  having  mounted  a  little  above  the  orifice, 
on  each  side,  they  dispose  of  a  portion  of  their  fibres  in  the 
substance  of  the  bladder.  A  smaller  and  somewhat  weaker 
set  of  fibres  will  be  seen  to  complete  their  course,  surrounding 
the  orifice  on  the  upper  part;  to  these  sphincter  fibres  a  bridle  is 
joined,  which  comes 'from  the  union  of  the  muscles  of  the  ure- 
ters."* 

After  repeated  observations  on  this  point,  I  have  come  to  the 
conclusion  that  Mr.  Bell  has  indicated  a  real  structure;  but  my 
own  dissections  have  resulted  as  follows:  The  inferior  semi- 
circumference  of  the  neck  of  the  bladder  is  surrounded  by  a 
thick  fasciculus  of  muscular  fibre,  half  an  inch  wide,  running 
in  a  transverse  direction,  and  having  its  ends  attached  to  the 
lateral  lobes  of  the  Prostate  Gland,  being  above  the  third  lobe 
of  the  latter.  This  fasciculus  is  perfectly  distinct  from  the  or- 
dinary muscular  fibre  of  the  bladder,  and  resembles  in  its  tex- 
ture the  musculo-fibrous  coat  of  the  arteries.  The  superior  se- 
micircumference  is  also  surrounded  by  a  thin  layer  of  muscular 
fibres  of  an  ordinary  kind,  forming  a  broad,  thin  band  of  a  cre- 
scentic  shape,  the  lower  ends  of  which  are  insensibly  lost  in  the 
adjacent  muscular  coat  of  the  bladder  by  being  spread  out.  And, 
lastly,  beneath  the  mucous  membrane  of  the  vesical  triangle 
there  is  a  triangular  muscle  of  the  same  size  as  the  triangle  with 
elongated  angles,  the  anterior  angle  of  which  may  be  traced  to 

*  Diseases  of  the  Urethra,  &c.  p.  10.     Lond.  1820. 


THE  BLADDER.  81 

the  posterior  part  of  the  caput  gallinaginis,  and  the  posterior 
angles  to  the  orifices  of  the  ureters  and  the  adjacent  part  of  the 
bladder.  The  texture  of  this  muscle  isralso,  like  that  of  the 
musculo-fibrous  coat  of  the  arteries.  When  a  bladder  is  recent, 
this  detail  of  structure  is  made  out  with  difficulty:  it  requires 
to  be  previously  hardened  in  spirits  of  wine.  That  a  power 
exists  in  the  neck  of  the  bladder  of  retaining  completely  the 
urine,  has  been  satisfactorily  demonstrated  to  me  in  a  case  of 
fistula  in  perineo,  which  was  presented  to  the  notice  of  Dr. 
Physick  and  myself,  a  few  years  ago.*  Occasionally  there  ex- 
ists on  each  side  of  the  neck  of  the  bladder,  passing  from  it  to 
the  pubes,  a  muscle  of  half  an  inch  in  breadth,  the  effect  of 
which  is  to  draw  the  neck  of  the  bladder  towards  the  symphysis 
pubis. 

As  the  urethra  of  the  male  performs  the  double  office  of  con- 
ducting both  semen  and  urine,  it  will  be  described  more  pro- 
perly along  with  the  organs  of  generation. 

The  urine  has  a  considerable  number  of  constituents,  the  pro- 
portion of  which  varies  according  to  age,  health,  and  other  cir- 
cumstances. Water  forms  about  nine-tenths  of  it,  the  remainder 
is  an  animal  matter  insoluble  in  alcohol;  uric  and  lactic  acids; 
lactate  of  ammonia;  sulphate  of  potash  and  of  soda;  hydrochlo- 
rate  of  soda  and  of  ammonia;  phosphate  of  soda  and  of  lime;  and 
fluate  of  lime. 

*  Chapman's  Med.  and  Phys.  Journ.  1824. 


BOOK  VI. 


Organs  of  Generation. 

CHAPTER  I. 

OF  THE  ORGANS  OF  GENERATION  IN  THE  MALE. 

THE  Male  Organs  of  Generation  consist  in  the  Testicles  and 
in  the  Penis,  with  their  appendages ;  or,  in  the  language  of  some 
anatomists,  in  the  Formative  and  in  the  Copulative  Organs;  which 
distinction  has  been  applied  to  both  sexes. 

SECT.  I. — OF  THE  PENIS. 

The  Penis,  (Membrum  Virile,  Menlula,)  from  performing  the 
two  offices,  one  of  which  is  the  conducting  of  urine  from  the 
bladder,  and  the  other  the  projection  of  semen  into  the  female, 
has,  accordingly,  a  peculiarity  of  structure,  which  allows  it  to 
assume  a  state  of  collapse  or  of  erection.  Its  shape  is  almost 
cylindrical,  but  terminating  in  front  by  an  obtusely  pointed  ex- 
tremity, named  Glans.  It  adheres  by  its  posterior  end  or  root 
to  the  bones  of  the  pelvis,  at  and  below  the  symphysis  pubis. 

It  is  formed  by  common  integuments,  by  condensed  cellular 
tissue,  by  the  Corpus  Cavernosum,  and  by. .the  Corpus  Spon- 
giosum. 

The  skin  on  the  penis  is  more  thin  and  delicate  than  it  is  on 
most  other  parts  of  the  body,  and  is  furnished  with  a  considera- 
ble number  of  sebaceous  follicles  or  glands  about  the  root  of  the 
organ,  with  hairs  'growing  from  the  centre  of  them.  This  same 


84  ORGANS  OF  GENERATION. 

skin,  in  passing  to  the  abdomen  over  the  pubes,  is  somewhat  pro- 
truded by  a  subjacent  deposite  of  fat  and  cellular  matter,  causing 
an  appearance  corresponding  with  the  mons  veneris  of  the  fe- 
male; and  is  also  generally  thickly  covered  with  short  curly 
hair,  which,  as  the  individual  advances  in  life,  proceeds  in  a 
pointed  direction  to  the  umbilicus.  The  skin  of  the  penis  is  but 
loosely  connected  to  the  organ,  so  that  it  slides  readily  back- 
wards and  forwards,  and  by  its  elasticity  is  well  suited  to  the 
varying  states  of  erection  and  collapse.  At  the  anterior  ex- 
tremity it  is  thrown  into  a  duplicature  or  fold;  the  Prepuce, 
(Preputium,)  the  internal  lamina  of  which  being  fixed  circularly 
to  the  penis,  some  distance  back  from  the  point,  permits  a  con- 
siderable portion  of  that  extremity  of  the  penis,  called  the  Glans, 
to  remain  uncovered  when  the  prepuce  is  drawn  back.  The 
under  middle  part  of  the  prepuce  is  attached  to  the  extremity  of 
the  glans  by  a  vertical  longitudinal  duplicature,  called  the  Frse- 
num,  which  extends  to  the  orifice  of  the  urethra. 

The  skin  does  not  actually  stop  at  the  circumference  of  the 
glans,  but  is  continued  smoothly  over  it,  modified,  however,  so 
much  in  its  structure,  as  to  be  much  more  adherent,  soft,  deli- 
cate, vascular,  and  sentient:  its  cuticle  there  is  a  thin  epithelium, 
readily  separated  by  maceration.  The  projecting  circular  and 
oblique  shoulder  of  the  glans,  behind  which  the  skin  becomes 
firmly  joined  to  the  penis,  is  called  the  Crown,  (Corona  Gldndis.) 
The  contracted  portion,  behind  the  corona,  is  the  neck,  (Collum.) 
On  the  surface  of  the  neck  and  the  posterior  face  of  the  corona, 
the  skin  is  furnished  with  an  abundance  of  small  glandular  masses 
or  follicles,  (Glandulce  Odorifera  Tysonii,)  which  secrete  the  thick 
white  sebaceous  matter,  (Smegma  praputei,}  that  accumulates 
when  personal  cleanliness  is  not  attended  to. 

The  penis,  in  addition  to  other  modes  of  attachment  to  the 
bones  of  the  pelvis,  is  fixed  by  the  Ligamentum  Suspensorium. 
The  latter  is  a  triangular  vertical  fibrous  lamina,  which  proceeds 
downwards  from  the  symphysis  pubis  to  the  dorsum  of  the  penis ; 
and,  according  to  Mr.  Colles,  envelops  this  organ  to  the  glans, 
forming  its  cellular  coat,  and  being  continued  into  the  fascia  su- 
perficialis  abdominis.  Posteriorly,  it  is  lost  insensibly  on  the 
fascia  of  the  thighs,  covering  the  adductor  muscles.  At  its  ori- 


THE  PENIS.  85 

gin  it  is  occasionally  furnished  with  muscular  fibres;  one  strongly 
marked  instance  of  which  has  been  presented  to  me  in  my  own 
dissections. 

The  Corpus  Cavernosum  of  the  penis,  forms  by  much  the  most 
considerable  portion  of  the  whole  organ.  Externally,  it  is  a 
white  fibrous  membrane,  of  a  dense  structure,  enjoying  extensi- 
bility and  an  extreme  degree  of  contractility.  Its  external 
fibres  pass,  for  the  most  part,  longitudinally,  except  about  the 
root,  where  they  are  blended  with  the  periosteum  of  the  bone, 
and  with  the  tendons  of  the  muscles.  This  coat  of  the  penis  is 
occasionally  called  its  elastic  ligament.  It  arises  by  two  conical 
crura,  from  the  internal  face  of  the  crura  of  the  pubes  and  ischia, 
to  within  a  little  distance  of  the  anterior  part  of  the  tuber  ischii. 
At  the  lower  part  of  the  symphysis  pubis  these  crura  join  and 
form  a  body;  which,  when  stripped  of  its  connexions,  resembles 
two  cylinders  lying  along  side  of  each  other,  united ;  and  which 
terminate  in  common,  anteriorly,  by  a  truncated  cone,  covered 
obliquely  by  the  glans.  At  the  posterior  part  of  the  corpus  ca- 
vernosum, in  its  centre,  there  is  a  septum,  almost  complete,  also 
of  the  same  elastic  substance,  which  separates  the  two  halves 
from  each  other;  but,  anteriorly,  this  septum  is  more  imperfect, 
having  an  arrangement  like  the  teeth  of  a  comb,  whence  the 
term  Septum  Pectiniforme  has  been  given  it.  This  septum  is 
continued  at  its  margins  into  a  layer  of  circular  fibres,  consti- 
tuting the  internal  coat  of  the  corpus  cavernosum. 

In  the  middle  of  the  corpus  cavernosum,  above,  is  a  longitudi- 
nal depression  for  lodging  the  veins  of  the  penis,  and,  in  the  same 
manner,  there  is  another  below,  for  the  corpus  spongiosum  ure- 
thrae.  The  cavity  of  this  membrane  is  filled  by  a  spongy  tissue, 
that  arises  from  its  internal  face,  and  is  formed  of  filaments  and 
little  laminae ;  they,  by  crossing  each  other,  make  a  multitude  of 
cells,  which  have  a  perfectly  free  communication  with  one  an- 
other, and  generally  are  somewhat  occupied  by  blood.  A  fine 
injection  through  the  artery  of  the  corpus  cavernosum  will  fill 
these  cells  and  return  through  the  veins ;  from  which  cause  the 
cells  may  be  considered  as  intermediate  to  the  two  orders  of 
vessels.  This  opinion  is  the  more  probable  from  the  cells  being 
lined  by  a  thin  menibrane  like  the  internal  one  of  the  veins,  and 
VOL.  II.— 12 


86  ORGANS  OF  GENERATION. 

which  is  easily  seen  near  the  septum  by  tearing  the  spongy  part 
from  it. 


The  Corpus  Spongiosum  Urethrae  extends  from  ten  or  twelve 
lines  behind  the  junction  of  the  crura  of  the  corpus  cavernosum, 
to  the  anterior  extremity  of  the  penis.  Externally,  it  has  a  coat 
resembling  that  of  the  corpus  cavernosum,  except  that  it  is  thin- 
ner, and  in  its  centre  is  the  canal  for  the  passage  of  urine.  Be- 
tween the  canal  and  the  coat  is  a  spongy  structure,  much  finer 
than  that  of  the  corpus  cavernosum,  and  though  the  cells  com- 
municate freely,  still  they  have  the  appearance  of  convoluted 
veins.  The  corpus  spongiosum  is  not  of  equal  diameter  in  its 
whole  course,  for  its  commencement  in  the  perineum,  where  it 
is  pendulous,  is  enlarged  into  what  is  termed  the  Bulb ;  from  this 
it  diminishes  gradually  to  the  anterior  end,  where  it  is  again  en- 
larged into  the  glans  penis. 

The  Urethra  is  a  canal,  whose  length  varies  according  to  the 
degree  of  erection  in  the  penis,  and  extends  from  the  neck  of  the 
bladder  to  the  extremity  of  the  glans.  It  is  curved,  and  receives 
in  its  course  the  ductus  ejaculatorii,  the  excretory  ducts  of  Cou- 
per's  glands,  and  the  mucous  lacunae  of  its  own  internal  mem- 
brane. The  first  part  of  this  canal  which  traverses  the  prostate 
gland  is  from  fifteen  to  eighteen  lines  in  length,  and  is  called  the- 
Prostatic  Portion:  it  is  well  supported  by  this  body,  although  its 
own  sides  are  very  thin.  On  its  inferior  surface  is  a  doubling 
which  constitutes  the  Verumontanum  or  Caput  Gallinaginis.  On 
either  side  of  the  caput  gallinaginis  the  canal  of  the  urethra  is 
depressed  into  something  like  a  cul-de-sac,  where  are  to  be  found 
the  lacunae  of  the  prostate  gland. 

Between  the  Prostate  and  the  Bulb  is  the  membranous  part 
of  the  urethra,  about  eight  or  ten  lines  long;  it  is  unprotected, 
except  by  a  soft  covering,  which  seems  in  some  measure  to  be 
a  mixture  of  gelatinous  matter  and  muscular  fibre.  The  former 
was  considered  by  Littre  as  a  glandular  body  which  secreted  a 
viscid  humour  into  the  interior  of  the  canal ;  the  latter,  probably, 
is  the  part  described  by  Winslow  as  the  inferior  prostatic  mus- 
cle ;  which,  arising  on  each  side  of  the  membranous  part  of  the 
urethra,  goes  to  be  inserted  into  the  corresponding  branch  of  the 


THE  PENIS.  87 

pubes  near  the  symphysis.  The  membranous  part  of  the  urethra 
does  not  get  into  the  end  of  the  bulb,  but  penetrates  it  from 
above,  half  an  inch  or  more  occasionally,  from  its  extremity, 
just  below  the  junction  of  the  crura  of  the  corpus  cavernosum. 

The  canal  varies  in  its  dimensions:  at  its  commencement, 
which  is  synonomous  with  the  neck  of  the  bladder,  it  is  large ; 
it  then  contracts  at  the  back  of  the  caput  gallinaginis,  and  imme- 
diately enlarges  in  the  fore  part  of  the  prostate,  at  the  sides  of 
the  caput.  The  membranous  part  is  small ;  the  canal  then  en- 
larges in  the  bulb.  In  the  body  of  the  penis  the  canal  is  suc- 
'  cessively  diminished,  till  it  comes  almost  to  the  glans,  when  it  is 
so  remarkably  enlarged  again  as  to  get  the  name  of  Fossa  Na- 
vicularis ;  it  terminates,  finally,  by  a  short  vertical  slit  at  the 
extremity  of  the  glans. 

In  the  whole  length  of  the  canal  there  are  two  whitish  middle 
lines,  one  above,  and  the  other  below ;  and  in  the  membranous 
and  spongy  portions,  excepting  the  fossa  navicularis,  longitudinal 
folds  of  the  lining  membrane  exist,  which  are  effaced  by  disten- 
tion.  In  the  upper  part  of  the  canal  there  are  a  great  many 
mucous  lacunae  ;*  Loder  has  marked  about  sixty-five :  there  is 
one  particularly  large  in  the  upper  surface  of  the  fossa  navicu- 
laris, which,  it  is  said,  has  stopped  the  point  of  a  bougie,  and 
been  mistaken  for  stricture.! 

Mr.  Shaw  Ras  described  a  set  of  vessels  immediately  on  the 
outside  of  the  internal  membrane  of  the  urethra ;  which,  when 
empty,  are  very  similar  in  appearance  to  muscular  fibres.  He 
says,  he  has  discovered  that  these  vessels  form  an  internal 
spongy  body,  which  passes  down  to  the  membranous  part  of  the 
urethra,  and  forms  even  a  small  bulb  there.f  His  preparation, 
being  a  quicksilver  injection  of  the  part,  is  certainly  a  very  sa- 
tisfactory demonstration  of  its  existence ;  yet,  in  my  own  obser- 
vations, where  the  blow-pipe  has  been  resorted  to,  it  has  rather 
appeared  to  me  to  be  the  cellular  membrane  connecting  the 
canal  of  the  urethra' with  the  corpus  spongiosum. 

*  Tabula  Anat. 

f  Sir  Everard  Home  has  lately  communicated  to  the  Royal  Society  a  highly 
interesting  paper  on  the  structure  of  the  lining  membrane  of  the  urethra.  From 
his  microscopical  observations  he  is  induced  to  think  that  it  is  muscular. 

t  Med.  Chir.  Trans.' vol.  x. 


88  ORGANS  OF  GENERATION. 

The  arteries  of  the  penis  come  from  the  internal  pudic ;  some 
of  its  veins  follow  the  course  of  the  arteries,  and  others  collect 
into  the  two  venae  dorsales  penis ;  the  nerves  come  from  the  in- 
ternal and  external  pudics. 


SECT,  II. OF  THE  MUCOUS  GLANDS  AND  APPARATUS. 

The  Seminal  Vesicles  ( Vesicula  Seminales)  are  two  convoluted 
tubes,  one  on  each  side,  two  inches  in  length,  placed  on  the 
lower  fundus  of  the  bladder,  between  it  and  the  rectum,  and  be- 
hind the  prostate  gland.  At  their  anterior  extremities  they  ap- 
proach very  nearly  to  each  other,  being  only  separated  by  the 
intervention  of  the  vasa  deferentia.  They  are  fixed  to  the  blad- 
der, and  surrounded  by  a  thick  mass  of  adipose  and  cellular 
matter,  with  many  blood  vessels,  principally  veins,  passing 
through  it. 

When  inflated  and  dried,  they  present  the  semblance  of  cells, 
but  are,  in  fact,  long  tubes;  which,  by  being  convoluted,  are 
reduced  to  the  apparent  dimensions  mentioned.  When  dissected 
and  stretched  out,  they  are  four  or  five  inches  long,  by  three 
lines  in  diameter. 

There  are  also  several  pouches  on  each  side  of  the  long  tube 
which  increase  the  number  of  cells.  The  convolutions  are  pre- 
served by  the  intermediate  cellular  tissue.  These  bodies  consist 
of  two  coats :  an  external,  which  is  fibrous  and  cellular ;  and  an 
internal,  which  is  mucous,  being  a  continuation  of  the  lining 
membrane  of  the  urethra.  They  are  commonly  filled  by  a  drab- 
coloured  thick  fluid,  supposed  to  be  a  mixture  of  the  semen,  with 
their  own  proper  secretion,  though,  of  this,  Mr.  Hunter  doubted.* 
The  excretory  duct  of  each  vesicle  is  about  a  line  and  a  half 
long,  when  it  joins  in  the  substance  of  the  prostate  with  the  vas 
deferens  of  the  same  side ;  a  common  canal  (ductus  ejaculalorius) 
is  thus  formed,  which  runs  parallel  with  its  fellow,  below  the  ure- 
thra.! 

*  Observations  on  the  Animal  (Economy. 

f  Lately,  in  a  dissection  executed  at  the  university  by  Dr.  Togno,  a  muscle 
was  found  on  the  inferior  surface  of  the  seminal  vesicles  arising  from  the  pros- 
tate gland,  and  inserted  into  them.  This  is  said  to  be  a  common  arrangement  in 
some  animals. 


MUCOUS  GLANDS.  89 

The  Ductus  Ejaculatorius  is  about  eight  or  ten  lines  long,  and 
opens  by  an  oblong  orifice,  at  the  lateral  anterior  face  of  the 
Caput  Gallinaginis :  it  is  larger  behind  than  before,  which  gives 
it  a  conical  shape,  and  allows  fluids  injected  to  pass  freely  from 
the  vas  deferens  to  the  vesicula,  and  the  reverse. 

The  Prostate  Gland  (Glandula  Parastala*}  is  a  body  about 
the  size  and  form  of  a  horse  chestnut,  fixed  on  the  neck  of  the 
bladder,  and  penetrated  by  the  urethra,  which  traverses  it  much 
nearer  its  superior  than  its  inferior  surface.  The  base  of  it  is 
turned  backwards,  and  the  point  forwards ;  its  inferior  surface 
rests  upon  the  rectum ;  it  is  rendered  concave  by  that  circum- 
stance, and  its  sides,  in  the  distentions  of  this  organ  by  faeces, 
are  overlapped  by  it.  The  Prostate  has,  posteriorly,  a  notch  in 
its  centre,  which  divides  it  into  two  lateral  lobes,  and  by  raising 
the  Vesiculae  Seminales,  we  see  where  their  excretory  ducts  pe- 
netrate the  gland,  and  separate  from  the  body  of  it,  the  little  tu- 
bercle, to  which  Sir  Everard  Homef  has  particularly  called  the 
attention  of  the  profession,  and  considered  as  a '  Third  Lobe ;  it 
being  certain  that  it  is  frequently  the  seat  of  disease  and  tume- 
faction. 

On  the  under  surface  of  the  canal  formed  in  the  prostate,  by 
the  urethra,  is  the  oblong  elevation  called  the  Verumontanum,  or 
Caput  Gallinaginis.  It  commences  a  little  in  front  of  the  uvula 
vesicse,  and,  being  broader  and  higher  behind,  comes  to  a  point 
very  gradually  before ;  it  is  about  eight  or  ten  lines  long.  Along 
the  posterior  part  of  this  ridge  is  a  long  cleft,  being  the  orifice  of 
a  lacuna,  first  observed  by  Morgagni ;  and  in  front  of  it  are  the 
orifices,  bordering  upon  each  other,  of  the  ductus  ejaculatorii. 

The  prostate  consists  in  a  condensed,  white,  extensible,  though 
easily  lacerated  fibrous  cellular  tissue,  within  which  are  placed 
a  great  number  of  mucous  follicles,  that  have  from  eight  to  twelve 
ducts,  or,  according  to  Loder,  from  thirty-two  t6  forty-four,  pass- 
ing obliquely  forwards,  and  terminating  in  the  urethra,  as  stated, 
at  the  sides  of  the  urethral  crest,  or  caput  gallinaginis.  The 
fluid  secreted  is  thick,  ropy,  white,  and  semi-transparent,  in  a 
healthy  state.  The  prostate  is  surrounded  by  a  fibrous  capsule, 
to  be  described. 

*  From  Vs-Xjtt/,  sto.  |  Diseases  of  Prostate. 


90  ORGANS  OF  GENERATION. 

The  lacunae  of  the  third  lobe  penetrate  the  coats  of  the  blad- 
der, behind  the  caput  gallinaginis. 

Of  the  Glands  of  Couper. — These  glands  are  also  intended  for 
the  secretion  of  mucus,  or  a  fluid  very  much  like  it,  into  the  ca- 
nal of  the  urethra.  They  are  two  in  number,  one  on  each  side, 
and  are  situated  in  advance  of  the  prostate,  between  the  laminae 
of  the  triangular  ligament,  at  the  point  where  the  bulb  of  the 
urethra  adheres  to  it.  Commonly,  they  are  about  the  size  of  a 
garden  pea,  but  not  unfrequently  much  smaller,  and,  in  some  in- 
stances, cannot  be  found  at  all,  which  induced  Hiester  to  declare, 
that  he  had  searched  for  them  fruitlessly.  They  are  yellowish, 
hard,  and  consist  of  several  lobules  united  together.  Each  one 
has  an  excretory  duct  that  receives  readily  a  bristle,  and  passes 
obliquely  forwards,  between  the  corpus  spongiosum  and  the  ca- 
nal of  the  urethra,  to  terminate  in  an  oblique  orifice  in  the  latter, 
about,  an  inch  distant  from  the  gland. 

One  or  more  glands,  of  the  same  description,  and  discovered 
by  Littre,  are  occasionally  found  just  in  front  of  Couper's.  They 
also  discharge  their  secretion  into  the  adjacent  part  of  the  ure- 
thra. In  my  own  dissections  I  have  not  met  with  them. 


SECT.  III. — OF  THE  TESTICLES. 

The  Testicles  (Testes,  Didymi)  are  two  in  number,  one  for 
each  side  of  the  scrotum.  Being  the  seat  of  the  secretion  of 
sperm  or  the  male  prolific  liquor,  their  function  is  of  the  first  im- 
portance in  the  act  of  generation.  They  are  of  an  oblong  oval 
form,  somewhat  compressed  laterally ;  and  present  their  edges 
forwards  and  backwards.  From  being  suspended  near  the  mid- 
dle of  their  posterior  edge  by  the  spermatic  chord,  the  upper 
end  points  somewhat  forwards,  while  the  lower  one  is  directed 
in  the  same  degree  backwards.  They  are  about  an  inch  and  a 
half  long,  by  one  inch  in  breadth,  and  eight  or  nine  lines  in  thick- 
ness. They  are  of  equal  size  generally,  but  in  case  of  a  diffe- 
rence it  is  in  favour  of  the  right;  the  latter  is  also  remarkable 
for  being  suspended  higher  than  the  left,  a  feature  in  ancient 
statuary  so  universal,  as  to  prove  the  vigilance  and 'accuracy 
of  the  sculptors  of  those  days,  in  regard  to  the  proportions  and 


THE  TESTICLES.  91 

peculiarities  of  the  human  form.  "  Two  obvious  advantages 
attend  this  arrangement:  one,  that  of  the  testicles  passing  each 
other  without  collision  when  the  thighs  are  brought  together ; 
and  another,  the  facility  of  keeping  the  penis  to  one  side,  instead 
of  straight  forward  in  the  middle  line  of  the  body."* 

The  testicle  is  enveloped  by  several  tunics;  they  are  the 
Scrotum,  the  Dartos,  the  Tunica  Vaginalis,  and  the  Tunica  Al- 
buginea. 

The  Scrotum  is  merely  a  continuation  of  the  common  skin 
from  the  inner  side  of  the  thighs,  the  perineum,  and  the  penis, 
and  is  common  to  the  two  testicles.  It  is  a  symmetrical  bag, 
and  the  two  halves  are  marked  off  from  each  other  by  a  middle 
line  or  elevation  of  the  skin,  called  the  Raphe,  which  begins  in 
the  perineum  at  the  anus,  and,  winding  around  ttye  scrotum,  is 
continued  along  the  under  surface  of  the  penis  to  the  prepuce. 

The  skin  of  the  scrotum  is  thin,  darker  than  elsewhere,  but 
has  a  thick,  strong  epidermis ;  it  has  many  sebaceous  follicles  in 
it,  and  is  sparingly  furnished  with  hair.  It  is  very  extensible,  as 
manifested  in  fatigue,  and  by  hydrocele  ;  and  may  be  contracted 
again  so  as  to  draw  the  testicles  close  under  the  pubes,  though 
for  the  latter  power  it  principally  depends  upon  the  subjacent 
coat.  Its  surface  is  covered  with  wrinkles,  for  the  most  part 
transverse,  and  ending  at  the  raphe :  they  are  effaced  during  its 
great  distentions  in  hernia  and  dropsy,  and  then  it  has  a  smooth 
shining  surface. 

The  Dartos  is  placed  within  the  scrotum,  and  forms  two  dis- 
tinct sacs  or  tunics,  one  for  each  testicle.  It  arises  from  the 
inferior  margins  of  the  crura  of  the  ischia  and  of  the  pubes,  and 
lines  the  scrotum  till  it  reaches  the  raphe ;  it  is  then  reflected 
upwards  to  form  the  partition  between  the  testicles,  (septum 
scroti,)  and  terminates  at  the  corpus  spongiosum  urethras.  This 
membrane,  according  to  the  observations  of  MM.  Chaussier, 
Lobstein,  and  Breschet,t  does  not  exist  in  the  scrotum  till  the 
descent  of  the  testicle,  and  then  appears  to  be  an  expansion  of 
the  gubernaculum  testis. 

*  gir  A.  Cooper  on  the  Testis.     1830. 

f  Dictionnaire  des  Sciences  Med.  tome  viK. 


92  ORGANS  OF  GENERATION. 

It  receives  a  considerable  number  of  blood  vessels,  which, 
owing  to  the  thinness  of  the  skin,  may  be  seen  in  the  living  body, 
ramifying  through  its  substance:  its  general  appearance  is, 
therefore,  reddish.  It  is  destitute  of  fat,  and  consists  in  long 
fibres  much  matted  together,  and  passing  in  every  direction : 
they  are  easily  separated  by  distention  with  air  or  water,  and 
by  slight  maceration.  Its  powers  of  contraction  are  exceeding- 
ly well  marked  upon  the  application  of  cold  to  the  scrotum,  from 
which  cause  it  has  been  considered  by  many  anatomists  as 
muscular :  the  only  distinct  evidences,  however,  which  I  have 
met  with  of  a  resemblance  to  the  latter,  have  been  found  gene- 
rally on  its  posterior  face,  near  the  perineum.*  From  its  equi- 
vocal character,  J.  F.  Meckel  has  very  ingeniously  suggested 
that  it  forms  the  transition  from  cellular  to  muscular  tissue,  and 
that  there  exists  between  it  and  other  muscles  the  same  relation 
that  there  is  between  the  muscles  of  the  superior  and  of  the  in- 
ferior orders  of  animals.  Among  the  latter,  the  fibrous  structure 
is  indistinctly  marked,  and  is  masked  by  gelatine;  an  element  of 
the  cellular  tissue  which  envelops  and  conceals  the  fibrine,  an 
element  of  the  muscular  tissue. 

The  fibres  of  the  cremaster  muscle,  which  are  next  in  order, 
form  a  very  imperfect  covering  to  the  testicle,  and  belong  rather 
to  the  spermatic  chord:  what  remains  to  be  said  concerning 
them  will  be  more  properly  introduced  into  the  account  of  the 
latter.  The  cellular  substance  that  connects  the  dartos  and  the 
cremaster  with  the  tunica  vaginalis  forms  a  compact  and  perfect 
lamina,  sometimes  spoken  of  as  the  Tunica  Vaginalis  Communis 
Testis.  There  is  one  for  each  testicle,  which  it  surrounds  en- 
tirely, as  well  as  its  chord,  and  connects  the  chord  to  the  mar- 
gins of  the  abdominal  rings,  as  stated  in  the  account  of  them. 
At  its  upper  end  it  is  continuous  with  the  cellular  substance  that 
unites  the  peritoneum  to  the  parietes  of  the  abdomen,  as  may 
be  proved  by  inflating  it,  when  the  air  will  penetrate  according- 
ly through  the  abdominal  canal. 

The  Peritestis,  or  Tunica  Vaginalis,  was  originally  a  process 

*  Since  the  first  edition,  I  have  dissected  one  subject,  (January,  1830,)  where 
the  fibres  were  evidently  muscular,  though  interwoven. 


THE  TESTICLES.  93 

of  peritoneum,  communicating  with  the  cavity  of  the  latter  through 
the  abdominal  canal ;  but  in  the  adult,  it  appears  as  a  complete 
and  distinct  sac.  As  it  is  very  rigidly  comparable  to  a  double 
night-cap  drawn  over  the  head,  we  accordingly  find  that  the  tes- 
ticle, along  with  the  epididymis,  is  pushed  into  it  from  behind. 
That  portion  of  the  tunica  vaginalis  which  is  in  contact  with  the 
testicle,  or  rather  with  the  tunica  albuginea,  adheres  so  closely 
that  it  cannot  be  separated,  except  very  partially,  and  in  shreds ; 
but  it  may  be  detached  easily  from  the  epididymis,  with  the  con- 
volutions of  which  it  is  in  immediate  contact.  This  sac  is  longer 
and  larger  than  the  testicle  itself,  from  which  cause  it  ascends 
for  several  lines  above  the  superior  end  of  the  gland,  and  the 
free  part  hangs  loosely  about  it.  Its  cavity  may,  with  but  little 
force,  be  injected  so  as  to  hold  an  ounce  or  two  of  fluid. 

This  membrane  is  smooth  and  polished  on  the  surface  forming 
its  cavity,  and  contains  a  small  quantity  of  serous  halitus,  which 
allows  the  opposed  surfaces  to  glide  freely  upon  one  another.  Its 
exterior  connexion  with  the  dartos  is  so  slight  that  it  may  be 
withdrawn  without  dissection,  with  the  exception  of  an  adhesion 
at  the  lower  end  of  the  testis  arising  from  the  remains  of  the  gu- 
bernaculum :  in  such  case,  however,  it  still  continues  to  be  in- 
vested by  the  tunica  vaginalis  communis,  from  which  it  can  only 
be  removed  by  a  special  dissection. 

The  Tunica  Albuginea  is  the  proper  coat  of  the  testicle,  is  in 
immediate  contact  with  its  glandular  structure,  and  serves  to 
maintain  its  shape,  as  well  as  to  protect  it  from  pressure.  From 
its  internal  surface  proceed  many  membranous,  horizontal  fibres, 
which  form  partial  partitions  of  its  cavity  (SeptulcB  Testis)  and 
incline  towards  its  posterior  part,  where  they  terminate  in  a  lon- 
gitudinal projection,  called  Corpus  Highmorianum.  The  latter 
is  of  a  prismatic  shape,  somewhat  broader  above  than  below, 
and  is  of  but  little  consequence,  except  that  it  was  once  errone- 
ously supposed  to  be  a  sinus,  into  which  the  seminiferous  tubes  dis- 
charged. Sir  Astley  Cooper  proposes  to  call  this  the  mediastinum 
testis,  and  considers  the  Corpus  Highmorianum  as  being  formed 
by  an  inflection  of  the  tunica  albuginea.  The  Septulae  Testis, 
he  asserts,  really  envelop  the  seminiferous  tubes,  by  forming  bags 
which  support,  confine,  protect,  and  nourish  .the  tubular  struc- 
VOL.  II.— 13 


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THE  TESTICLES.  05 

backwards  to  penetrate  the  corpus  Highmoriamnn  and  the  tunica 

albuginea.  f  these  vasa  efferentia  is  then  convoluted  upon 

nical  body,  called  Conns  Vasculosus,  which  pre- 

:ts  base  backwards.    Each  cone,  at  its  base,  has  its  tube 

entering  successively  into  the  tube  of  which  the  Epididyrnis  is 

Notwithstanding  the  extreme  tenuity  of  these  several  arrange- 
ments in  the  excretory  ducts  of  the  testicle,  they  may  be  entirely 
filled  with  quicksilver  from  the  vas  deferens ;  but  the  task  is  one 
of  great  difficulty,  and  rarely* succeeds. 

The  epididyrnis  is  the  prismatic  arch  which  rests  vertically  on 
the  back  of  th'  and  adheres  to  it  by  the  reflection  of  the 

tunica  vaginalis.    It  is  enlarged  at  both  ends,  the  upper  of  which 
formed  by  the  Coni  Vasculosi,  is  called  the  Globus  Major, 
and  the  lower  enlargement  is  the  Globus  Minor.    It  is  formed  of 
a  single  convoluted  tube,  of  the  fourth  of  a  line  in  diameter. 
After  this  tube  has  got  to  the  lower  end  of  the  globus  minor  it 
.ics  less  convoluted,  enlarges,  turns  upwards  on  the  inner 
f  the  epididymis,  and  obtains  the  name  of  Vas  Deferens. 
Before  it  reaches  the  top  of  the  epididymis  it  has  become  per- 
fectly straight,  or  almost  so.    There  is  a  blind  duct  which  be- 
gins at  the  top  of  the  epididymis  and  terminates  below ;  the  ob- 
ject of  it  is  not  understood. 

Of  the  Spermatic  Chord. 

The  Spermatic  Chord  is  a  fasciculus  of  about  half  an  inch  in 
diameter,  which  may  be  felt  very  readily  through  the  skin  of  the 
scrotum,  passing  from  the  upper  end  of  the  testicle  to  the  exter- 
nal abdominal  ring.  It  is  formed  by  the  Vas  Deferens :  the  Sper- 
matic Artery  and  Veins :  the  Lymphatics  of  the  Testicle ;  and 
i  being  covered  in  by  the  Tunica  Vaginalis  Com- 
munis,  and  by  the  Cremaster  Muscle. 

The  Cremqster  Muscle,  also  called  the  tunica  elythroides,*  be- 
ing derived  from  the  internal  oblique  and  the  transverse  muscle  of 
the  abdomen,t  forms  a  very  complete  envelope  to  the  chord  from 

*  E/.y7^r,  a  sheath.  f  See  Abdominal  Muscles. 


96  ORGANS  OF  GENERATION. 

the  abdominal  ring  to  the  testicle.  But  when  it  reaches  the  lat- 
ter its  fibres  spread  out  and  become  indistinct  upon  the  tunica 
vaginalis  communis,,  as  they  there  consist  in  small,  pale,  scat- 
tered fasciculi ;  many  of  which  terminate  insensibly,  while  others 
form  on  the  front  of  the  tunica  vaginalis  loops,  having  their 
convexities  downwards.  This  muscle  draws  the  testicle  up- 
wards, an  action  very  different  from  the  corrugation  of  the 
scrotum. 

The  Vas  Deferens,  or  the  proper 'excretory  duct  of  the  testicle, 
is  a  white  tube  of  about  a  line  and  a  half  in  diameter,  and  has  a 
cartilaginous  feel.  Its  parietes  are  thick,  as  its  cavity  will  not 
receive  a  body  larger  than  a  bristle,  without  being  put  upon  the 
stretch.  It  traverses  a  long  space,  and  in  doing  so,  first  passes 
at  the  back  of  the  chord  from  its  commencement  to  the  internal 
abdominal  ring :  having  reached  the  latter,  it  then  abandons  the 
spermatic  artery  and  vein,  and  dipping  into  the  pelvis,  by  the 
side  of  the  bladder,  goes  between  the  lower  fundus  of  the  latter 
and  the  ureter.  It  then  converges  towards  its  fellow,  along  the 
under  extremity  of  the  bladder,  at  the  inner  margin  of  the  vesi- 
cula  seminalis,  of  the  same  side,  and  finally  terminates  in  the  ure- 
thra near  the  neck  of  the  bladder,  by  forming  the  Ductus  Ejacu- 
latorius  with  the  assistance  of  the  duct  of  the  adjoining  vesicula 
seminalis.  About  two  and  a  half  inches  from  its  termination,  it 
enlarges  and  becomes  somewhat  tortuous. 

This  duct  consists  of  two  coats :  the  external  one  is  hard,  com- 
pact, and,  occasionally,  fibres  are  seen  in  it ;  but  its  structure  is 
not  very  evident,  and  is  peculiar.  The  internal  is  a  mucous 
membrane. 

For  the  description  of  the  remaining  portions  of  the  chord, 
see  Spermatic  Artery,  Vein,  Lymphatics,  and  Plexus  of  Nerves. 

The  Testicles  undergo  a  remarkable  change  in  their  position, 
from  the  earliest  development  of  their  rudiments  to  the  perfect 
foetal  state.  They  are  not  formed  in  the  scrotum,  but  in  the  ab- 
domen just  below  the  kidneys ;  from  which  position  they  are 
gradually  transferred.  About  the  middle  of  the  third  month  of 
gestation  they  are  two  lines  long,  and  placed  behind  the  perito- 
neum, to  which  they  loosely  adhere.  The  vas  defer  ens  then,  in- 


MUSCLES  AND  FASCIA  OF  THE  PERINEUM.  97 

stead  of  rising  up  on  the  side  of  the  epididymis,  goes  straight 
down  into  the  pelvis.  At  this  period  may  be  seen  the  guberna- 
culum  testis,  discovered  by  J.  Hunter,*  which  becomes  more  dis- 
tinct in  a  few  weeks  afterwards,  and  assumes  a  triangular  appear- 
ance. This  gubernaculum  has  the  office  of  drawing  the  testicle 
down  into  the  scrotum ;  its  point  commences  in  the  upper  part  of 
the  latter,  somewhat  below  the  external  abdominal  ring ;  it  passes 
through  the  abdominal  canal,  ascends  upon  the  iliac  us  internus 
muscle,  and  is  attached  by  its  base  to  the  inferior  end  of  the  tes- 
ticle. In  front  of  the  gubernaculum,  a  process,  or  small  pouch 
of  peritoneum,  passes  through  the  abdominal  canal  to  the  upper 
part  of  the  scrotum.  By  the  contraction  of  the  gubernaculum, 
the  testicle  is  brought,  about  the  seventh  or  eighth  month,  into 
the  scrotum,  by  sliding  down  behind  the  pouch.  The  lower  end 
of  the  pouch,  at  which  the  testicle  is  finally  arrested,  becomes 
the  tunica  vaginalis  testis. 

As  soon  as  the  testicle  has  reached  the  scrotum,  the  neck  of 
the  pouch  has  a  tendency  to  close  and  to  become  obliterated, 
which  is  commonly  accomplished  at  the  period  of  birth ;  yet  it 
sometimes  remains  open  for  a  longer  time,  and  becomes  the  oc- 
casion of  congenital  hernia.  Very  generally,  at  birth,  the  orifice 
of  the  pouch  will  receive  the  end  of  a  probe  to  the  depth  of  a  line 
or  two ;  but  all  below  is  perfectly  closed,  and  has  its  structure 
so  condensed  and  altered,  that  na  one,  from  a  view  of  it  alone, 
would  suppose  that  the  cavity  of  the  tunica  vaginalis  had  ever 
communicated  with  that  of  the  peritoneum.t 


SECT.  IV. — OF  THE  MUSCLES  AND  FASCIA  OF  THE  PERINEUM. 

Perineal  Fascia. 
The  Perineal  Fascia  is  placed  just  beneath  the  skin  of  the  peri- 

*  Mecl.  Comment.  Lond.  1777. 

j-  The  explanations  and  anatomy  of  this  process  have  been  treated  at  large  in 
the  following  works  : 

Girardi,  Tabul.  II.  adj.  Septemd.  Tab.  Santorini. 

Hunter,  Observations  on  certain  parts  of  the  Animal  (Economy.  W.  Hunter, 
Med.  Commentaries. 

Edwardi  Sandifort,  Opusc.  Anat. 

Wrisberg  Comment.  Medic.  Physiolog.  &c. 


98  ORGANS  OP  GENERATION. 

neum,  and  covers  the  muscles.  It  occupies  nearly  all  the  space 
between  the  anus  and  the  posterior  margin  of  the  scrotum,  and 
between  the  rami  of  the  pubes  and  the  ischia  on  each  side :  it  is 
very  firmly  fixed  to  these  bones,  and  is  gradually  blended  with 
the  cellular  substance  of  the  posterior  part  of  the  scrotum.  This 
fascia  is  rather  thin,  but,  in  case  of  a  rupture  of  the  posterior  part 
of  the  urethra,  prevents  the  urine  from  showing  itself  in  the  peri- 
neum, and  drives  it  into  the  cellular  structure  of  the  scrotum. — 
In  abscesses  of  the  perineum,  it  also  prevents  the  fluctuation  from 
being  very  evident. 

The  Musculus  Erector  Penis, 

Is  so  situated,  as  to  cover  the  whole  of  the  crus  of  the  penis 
which  is  not  in  contact  with  the  bony  margin  of  the  pelvis.  It 
arises,  therefore,  tendinous  and  fleshy,  from  the  anterior  part  of 
the  tuber  ischii;  its  fleshy  fibres  adhere  to  the  internal  and  exter- 
nal margins  of  the  ramus  of  the  ischium,  and  of  the  pubes,  and 
proceed  upwards;  just  before  the  union  of  the  crura  of  the  pe- 
nis, they  end  in  a  flat  tendon  which  is  lost  on  the  side  of  the 
corpus  cavernosum  of  the  penis.* 

Its  use  is  not  well  understood. 

The  Musculus  Accelerator  Urince, 
« 

Lies  on  the  bulb  and  back  part  of  the  corpus  spongiosum  ure- 
thras :  it  is  a  thin  muscle,  consisting  of  oblique  fibres. 

It  arises  by  a  pointed  production  from  the  side  of  the  body  of 
the  penis ;  its  origin  is  continued  obliquely  across  the  inferior  sur- 
face of  the  crus  penis,  where  the  latter  begins  to  form  the  body 
of  the  penis.  It  arises,  also,  for  an  inch  from  the  inner  side  of 
the  ramus  of  the  pubes,  between  the  crus  penis  and  the  triangu- 
lar ligament  of  the  urethra.  The  muscles  of  the  opposite  sides 
are  inserted  into  one  another  by  a  white  line,  which  marks  the 
middle  of  the  bulb  of  the  urethra ;  and  by  a  point,  into  the  ante- 
rior extremity  of  the  sphincter  ani,  where  they  are  joined  by  the 
transversi  perinei. 

*  The  late  Dr.  Lawrence  informed  me  that  he  had  frequently  found  muscular 
fibres  between  the  bone  and  the  cms  penis. 


MUSCLES  OF  THE  FASCIA  AND  PERINEUM.  99 

In  order  to  see  the  origin  of  these  muscles  very  distinctly,  se- 
parate them  from  each  other  in  the  middle  line,  and  dissect  them 
from  the  corpus  spongiosum.  Cut  transversely  through  the  cor- 
pus spongiosum  about  three  inches  before  the  triangular  liga- 
ment, and  dissect  it  clearly  from  the  corpus  cavernosum,  turning 
it  downwards  so  that  it  may  hang  by  the  membranous  part  of 
the  urethra.  By  putting  the  two  acceleratores  on.  the  stretch,  it 
will  be  seen  that  besides  the  origins  mentioned,  they  arise,  also, 
from  each  other  by  a  tendinous  membrane  that  is  interposed  be- 
tween the  corpus  spongiosum  and  cavernosum ;  so  that  they  lite- 
rally surround  the  back  part  of  the  urethra,  constituting  a  com- 
plete sphincter  muscle  for  it.  This  account  of  the  accelerator 
urinae  being  peculiar  to  myself,  is  adopted  from  a  strong  analogy 
between  it  and  the  sphincter  vaginae. 

The  two  muscles  are  considered  by  M.  Chaussier  as  forming 
but  one :  in  that  case  its  origin  will  be  reversed,  and  commence 
in  the  middle  line  of  the  perineum  instead  of  terminating  there. 
As  this  muscle,  and  the  erector  penis,  touch  by  their  contiguous 
faces,  it  is  difficult  to  get  into  the  membranous  part  of  the  ure- 
thra in  lithotomy  without  cutting  through  the  muscular  fibres  of 
one  or  the  other. 

It  propels  the  urine  and  semen  forward. 

The  Musculus  Transversus  Perinei, 

As  its  name  implies,  passes  directly  across  the  perineum ;  it 
arises  from  the  inner  side  of  the  ischium,  just  at  the  origin  of  the 
erector  penis,  and  is  inserted  where  the  sphincter  ani  and  acce- 
leratores join. 

I  have  observed  that  when  the  lower  part  of  the  accelerator 
was  extended  much  below  its  usual  line,  and  strongly  developed, 
that  the  transversus  was  very  irregular  in  its  origin  and  course ; 
consisting  frequently  of  a  few  fibres  which  did  not  deserve  the 
name  of  a  distinct  muscle,  and  lying  almost  unappropriated  in 
the  adipose  matter  of  the  part. 

Occasionally,  a  fasciculus  of  muscular  fibres  exists,  called,  by 
Albinus,  Transversus  Perinei  Alter,  which  arises  in  front  of  the 
transversus :  it  seems  generally  to  be  a  fasciculus  loosened  of 


100  ORGANS  OF   GENERATION. 

the  accelerator  urinae  muscle,  and  is  inserted  into  the  perineal 
junction  just  behind  it. 

The  use  of  these  muscles  seems  to  be  to  contribute  to  fix  the 
bulb  of  the  urethra. 


The  Musculus  Sphincter  Ani, 

Consists  in  a  plane  an  inch  thick,  of  elliptical  fibres  immediate- 
ly beneath  the  skin  of  the  anus,  and  which  surrounds  the  latter 
in  order  to  keep  it  closed.  The  long  diameter  of  the  ellipsis  is 
extended  from  the  coccyx  towards  the  symphysis  pubis,  and 
has  its  angles  very  much  elongated :  the  anterior  may  be  traced 
terminating  insensibly  in  the  posterior  face  of  the  scrotum.  It 
has  two  fixed  points,  the  last  bone  of  the  os  coccygis  behind,  and 
the  perineal  union  of  the  other  muscles  in  front ;  its  lateral  dia- 
meter occupies  about  one-half  of  the  space  between  the  tuberosi- 
ties  of  the  ischia,  and  it  is  in  the  middle  of  this  space. 

Besides  closing  the  orifice  of  the  rectum  it  will  draw  the  bulb 
of  the  urethra  backwards,  or  the  point  of  the  os  coccygis  for- 
wards. 

The  Musculus  Coccygeus, 

Belongs  to  the  interior  of  the  pelvis.  It  arises  by  a  small, 
tendinous,  and  fleshy  beginning,  from  the  spine  of  the  ischium, 
and,  lying  on  the  anterior  face  of  the  anterior  sacro-sciatic  liga- 
ment, it  is  inserted  into  the  side  of  the  last  bone  of  the  sacrum, 
and  of  all  those  of  the  os  coccygis. 

It  draws  the  os  coccygis  forwards. 

It  frequently  happens  that  there  is  on  each  side  a  small  fasci- 
culus of  muscle  arising  from  the  inferior  bone  of  the  sacrum  in 
front,  and  inserted  into  the  bones  of  the  coccyx ;  it  is  called 
Sacro-Coccygeus. 

A  large  quantity  of  adipose  and  cellular  matter  exists  on  the 
side  of  the  rectum,  between  it  and  the  parietes  of  the  pelvis,  con- 
cealing the  perineal  surface  of  the  levatores  ani  muscles. 


MUSCLES  AND  FASCIA  OF  THE  PERINEUM.  101 

The  Musculus  Levator  Ani, 

Arises,  fleshy,  from  the  back  of  the  pubes  near  its  symphysis, 
and  from  near  the  superior  margin  of  the  foramen  thyroideum 
above  the  obturator  internus  muscle.  It  also  arises  from  the 
aponeurosis  pelvic  a,  where  this  membrane  is  extended  as  a 
thickened  semi-lunar  chord  from  the  superior  margin  of  the  thy- 
roid foramen  towards-  the  spinous  process  of  the  os  ischium. 
This  second  part  of  the  origin  of  the  levator  ani  is  defectively 
described  in  most  books  on  anatomy.  It  is  then  seen  to  cross 
obliquely,  as  far  as  the  spine  of  the  ischium,  that  portion  of  the 
obturator  internus  which  arises  from  the  plane  of  the  ischium. 

From  this  extensive  origin  the  •  fibres  converge  and  descend 
backwards,  and  have  three  distinct  places  of  insertion;  the  pos- 
terior fibres  are  inserted  into  the  two  last  bones  of  the  os  coccy- 
gis;  the  middle,  and  by  far  the  greater,  number,  are  inserted 
into  the  semi-circumference  of  the  rectum  be'tween  its  longitu- 
dinal fibres  and  the  circular  fibres  of  the  sphincter  ani;  and, 
finally,  the  most  anterior  fibres  pass  obliquely  downwards  and 
backwards  on  the  side  of  the  vesical  end  of  the  membranous 
part  of  the  urethra,  and  on  the  side  of  the  prostate  gland,  and 
are  inserted  into  the  common  place  of  junction  of  the  perinea! 
muscles. 


The  Triangular  Ligament  of  the  Urethra, 

Is  a  membrane  which  fills  up  the  space  below  the  symphysis 
of  the  pubes,  and  answers  there  as  a  septum  between  the  peri- 
neum and  the  pelvis:  when  closely  examined,  it  is  seen  to  con- 
nect itself  to  the  internal  edges  of  the  rami  of  the  pubes  and 
ischia  on  the  inner  posterior  sides  of  the  crura  penis  as  far  down 
as  the  beginning  of  the  latter.  At  its  lower  edge  its  ligamentous 
character  is  not  so  well  defined.  On  its  anterior  surface  is  the 
bulb  of  the  urethra,  and  just  at  the  extremity  of  the  latter,  en- 
closed by  the  ligament,  and  adhering  to  it,  are  Couper's  Glands. 
In  contact  with  it  behind,  and  adhering,  is  the  prostate  gland, 
covered  by  its  fibrous  capsule,  which  is  a  continuation  of  the 
pelvic  aponeurosis  over  it.  A  perforation  exists  in  it,  through 
VOL.  II.— 14 


102  ORGANS  OF  GENERATION. 

which  passes  the  membranous  part  of  the  urethra.  This  open- 
ing is  not  very  apparent,  in  consequence  of  its  edges  being  con- 
tinued a  little  distance  on  the  canal ;  but  by  detaching  them  the 
whole  becomes  well  defined. 

The  relative  situation  of  the  bulb  and  of  the  membranous  part 
of  the  urethra  is  such,  that  the  former  goes  towards  the  anus, 
while  the  latter  passes  upwards  towards  the  neck  of  the  bladder ; 
they,  consequently,  form  a  considerable  angle  with  each  other. 
The  membranous  part  of  the  urethra  is  much  the  deepest,  the 
recollection  of  which  is  all-important  in  lithotomy,  as  it  teaches 
us  to  avoid  the  one,  and  to  cut  into  the  other.  It  may  also  be 
observed,  that  the  hole  in  the  triangular  ligament  is  an  inch  be- 
low the  symphysis  pubis. 

By  removing  the  upper  corner  of  the  triangular  ligament,  we 
are  made  acquainted  with  another  just  behind  it,  which  is  total- 
ly distinct.  This  ligament  is  half  an  inch  broad,  is  thick  and 
strong,  particularly  at  its  lower  edge,  and  is  very  firmly  attached 
laterally  to  each  of  the  pubes,  just  below  the  symphysis:  it  is  a 
continuation  of  the  ligamentous  union  of  the  symphysis  pubis. 
Mr.  Colles  calls  it  pubic  ligament,  with  great  propriety.  I  would 
suggest,  as  somewhat  more  expressive,  the  term  Inter-Pubic  Li- 
gament ;  *  as  it  serves  to  distinguish  it  from  another  called  Pubic, 
which  is  above  the  pubes,  and  described  in  the  account  of  the 
recti  abdominis  muscles.  The  breadth  of  this  having  been 
stated  at  half  an  inch,  it  is  obvious  that  the  hole  in  the  triangu- 
lar ligament  is  half  an  inch  below  its  lower  edge. 

Pelvic  Fascia. 

The  Pelvic  Fascia  (Aponeurosis  Pelvica)  connects  the  bladder 
to  the  sides  of  the  pelvis.  "  This  fascia  descends  from  the  ileo- 
pectineal  line  to  about  midway  in  the  depth  of  the  pelvis;  here 
it  is  reflected  from  the  surface  of  the  muscle,  (the  Levator  Ani,) 
and  applies  itself  to  the  prostate  gland  and  bladder  on  the  body 
of  which  it  is  ultimately  lost.  At  the  angle  of  its  reflection,  this 
fascia  appears  particularly  strong  and  white,  but  becomes  more 
weak  and  thin  as  it  lines  the  muscle  and  covers  the  bladder.  In 

*  See  Symphysis  Pubis. 


MUSCLES  AND  FASCIA  OP  THE  PERINEUM.  103 

tracing  this  membrane  it  will  be  seen  that  from  the  pubes  just 
below  the  symphysis,  a  pointed  production  of  it,  constituting  its 
anterior  margin,  is  fixed  into  the  side  of  the  neck  of  the  bladder. 
This  pointed  production  on  each  side  is  called,  by  most  anato- 
mists, the  anterior  ligaments  of  the  bladder.  Between  them, 
just  beneath  the  symphysis  of  the  pubes,  a  pouoh  large  enough 
to  receive  the  end  of  the  finger,  is  formed  by  the  union  of  the 
fasciae  of  the  two  sides:  this  pouch  connects  the  middle  anterior 
part  of  the  neck  of  the  bladder  to  the  lower  margin  cf  the  sym- 
physis pubis."* 

This  fascia  adheres  closely  to  the  periosteum  of  the  pubes, 
between  the  upper  margin  of  the  thyroid  foramen  and  the  crista 
of  the  pubes ;  about  the  middle  third  of  the  linea  innominata  it  is 
obviously  a  continuous  membrane  with  the  iliac  fascia  which 
covers  the  iliacus  internus  muscle;  but  behind  this,  again,  it 
arises  from  the  remaining  third  of  the  linea  innominata. 

The  portion  of  this  fascia  which  Mr.  Colles  speaks  of  as  pap* 
ticularly  strong  and  white,  forms  a  bow,  the  concavity  of  which 
looks  upwards^  one  end  of  the  bow  being  fastened  to  the  pubes 
above  the  foramen  thyroideum,  and  the  other  end  to  the  ischium 
above  its  spine.  The  perineal  surface  of  this  bow  is  an  impor- 
tant point  of  the  origin  of  the  levator  ani.  Above  the  bow  this 
fascia  is  very  thin,  for  the  fibres  of  the  obturator  internus  can  be 
readily  seen  through  it. 

At  the  bow  the  fascia  divides  into  two  laminae;  one  pursuing 
its  course  to  the  bladder  and  rectum,  the  other  covers  the  lower 
part  of  the  obturator  internus  muscle,  and  thereby  constitutes 
the  obturator  fascia.  The  levator  ani  is  interposed  between  the 
two  laminae.  The  aponeurosis  pelvica  also  forms  a  bow  or  se- 
mi-lunar edge  in  front  of  the  sacral  nerves.  The  triangular  li- 
gament and  this  fascia  are  so  identified  in  forming  the  capsule  of 
the  prostate,  that  the  latter,  in  description,  may  be  referred  either 
to  the  one  or  the  other,  or  to  both,  according  to  the  fancy  of  the 
describer. 

*  Colics'  Surgical  Anatomy. 


104  ORGANS  O.F  GENERATION. 


CHAPTER  II. 


OF  THE  ORGANS  OF  GENERATION  IN  THE  FEMALE. 

THE  Copulative  Organs  in  the  female  are,  the  Vulva  and  the 
Vagina;  the  Generative  are  the  Uterus  and  the  Ovaria. 


SECT.  I. — OF  THE  VULVA. 

The  term  Vulva  is  applied  to  the  most  superficial  of  the  co- 
pulative organs,  and  consists  in  the  Mons  Veneris,  the  Labia 
Externa,  the  Labia  Interna,  the  Clitoris,  the  Vestibulum,  the 
Orificium  Urethrae,  the  Fourchette,  and  the  Fossa  Navicularis. 

The  Mons  Veneris  is  the  protuberance  on  the  fore  part  of  the 
pubes.  Its  size  varies  considerably,  according  to  the  state  of 
obesity  of  the  subject,  in  consequence  of  its  being  formed  by  a 
deposite  of  fat  between  the  skin  and  the  bone:  in  corpulent 
women  it  is  very  large  and  prominent,  whereas,  in  such  as  are 
much  emaciated,  it  simply  describes  the  outline  of  the  bones. 
The  skin,  there,  is  abundantly  furnished  with  sebaceous  glands, 
seated  in  the  cellular  texture  beneath  it,  and  about  the  size  and 
shape  of  millet  seed.  At  the  age  of  puberty  a  growth  of  hair 
takes  place  upon  it,  which  is  not  so  long  as  the  correspondent 
growth  upon  men,  and  is  not  so  much  disposed  to  spread  itself 
over  the  lower  part  of  the  abdomen  as  life  advances.  In  wo- 
men who  have  abused  coition,  it  is.  said  that  these  hairs  become 
much  curled. 

The  Labia  Externa  are  a  continuation  of  the  mons  veneris 
downwards  in  the  form  of  an  oblong  eminence  on  either  side. 
Their  elevation  is  produced  in  the  same  way  by  a  deposite  of 
fat  beneath  the  skin.  They  are  somewhat  broader  and  more 
prominent  above  than  below.  On  the  side  which  is  next  to  the 
thigh,  the  integument  is  common  skin,  sparingly  covered  with 
hair;  but  on  the  other  face  it  is  a  mucous  membrane,  being  a 
continuation  of  that  of  the  vagina.  The  skin  here,  as  well  as 


THE  VULVA.  105 

at  the  commencement  of  every  mucous  membrane,  is  insensi- 
bly changed  into  the  latter.  They  have  many  sebaceous  glands 
externally,  and  mucous  glands  internally,  upon  them. 

Much  cellular  membrane,  like  that  of  the  scrotum,  is  found 
in  their  interior  structure;  whereby  they  enjoy  great  extensibi- 
lity in  order  to  favour  the  dilatation  of  the  parts  in  parturition. 
The  rima  which  exists  between  them  is  the  Fissura  Vulvas  of 
authors,  and  is  about  twice  the  length  of  the  orifice  of  the  vagiT 
na;  this  arrangement  of  it  gives  increased  facility  to  the  expul- 
sion of  the  fostus. 

The  Fourchette  or  Frenulum  Vulvse,  is  situated  at  the  poste- 
rior commissure  of  the  labia  externa,  and  is  a  thin,  narrow 
transverse  duplicature  of  skin;  which,  owing  to  its  weakness,  is 
most  frequently  ruptured  at  the  first  act  of  parturition,  and  then 
disappears. 

The  Clitoris  bears,  in  some  respects,  a  resemblance  to  the  penis 
of  the  male,  but  is  by  ho  means  so  large.  It  is  situated  imme- 
diately below  the  symphysis  pubis,  and  consists  in  a  cylindrical 
body  of  three  or  four  lines  in  diameter,  with  two  crura.  The 
body  is  an  inch  long;  the  crura  are  likewise  of  the  same  length, 
and  arising  from  the  internal  face  of  the  crura  of  the  pubes, 
unite  beneath  the  symphysis  so  as  to  form  the  body.  The 
body  is  not  straight,  but  has  the  anterior  half  bent  downwards 
and  forwards.  The  exterior  covering,  or  capsule  of  the  clitoris, 
in  its  texture,  resembles  the  elastic  ligamentous  membrane  of 
the  corpus  cavernosum  penis;  and  is,  moreover,  filled  within  by 
a  similar  cavernous  or  cellular  structure,  which  is  divided  into 
two  equal  parts  by  a  septum  pectiniforme,  and  is  susceptible  of 
distention  during  sexual  excitement.  The  clitoris  is  supplied 
also  with  blood  vessels  and  nerves  like  the  penis,  and  is  held 
up  to  the  under  part  of  the  symphysis  pubis  by  a  suspensory 
ligament. 

The  anterior  extremity  of  the  body  of  the  clitoris  is  found  in 
the  rima  or  fissura  vulvae,  about  an  inch  below  the  upper  com- 
missure 6*f  the  labia  externa.  It  projects  somewhat,  and  bears 
a  general  resemblance  in  shape  with  the  end  of  the  penis, 
whence  its  name  of  glans  clitoridis;  but  it  has  not  the  same  or 


106  ORGANS  OP  GENERATION. 

i 

ganization,  excepting  the  delicacy,  the  extreme  sensibility,  and 
the  vascularity  of  the  skin  which  covers  it.  The  clitoris  has  no 
corpus  spongiosum,  neither  is  it  concerned,  like  the  penis,  in 
conveying  the  urine  from  the  bladder.  Its  glans  is  covered  by 
a  doubling  of  skin  called  the  prepuce,  and  is  likewise  furnished 
with  the  glandulae  Tysoni,  from  which  is  discharged  a  smegna, 
or  sebaceous  fluid,  as  in  the  male.  The  prepuce  does  not  fur- 
nish a  regular  well  defined  fraenum. 

The  Erector  Clitoridis  muscle  corresponds  with  the  erector 
penis.  It  arises  from  the  ascending  ramus  of  the  ischium,  and, 
covering  the  inferior  face  of  the  cms  clitoridis,  runs  as  far  for- 
wards as  the  commencement  of  the  body. 

The  Labia  Interna,  or  Nymphae,  are  two  duplicatures  of  the 
mucous  membrane  of  the  vulva,  which  pass  down,  one  on  each 
side,  from  the  clitoris.  The  prepuce  of  the  latter  terminates, 
on  either  side,  in  the  labia;  while  the  latter  are  continued  up- 
wards, by  a  narrow  process,  to  the  under  surface  of  the  glans 
clitoris.  They  arise,  all  along  their  base,  from  the  internal  sides 
of  the  labia  externa,  or  majora;  and  being  wider  in  the  middle 
than  elsewhere,  they  terminate  insensibly  about  half-way  down 
the  orifice  of  the  vagina.  Between  the  laminae  of  each  one  is 
placed  a  vascular  cellular  substance,  susceptible  of  distention  and 
of  partial  erection  during  sexual  excitement.  In  young  sub- 
jects, their  vascularity  communicates  a  vermilion  tinge,  which 
is  lost  and  becomes  brownish  in  the  progress  of  life.  As  they 
are  effaced  during  parturition,  their  chief  use  seems  to  be  a  pro- 
vision for  the  great  distention  of  the  vulva,  which  then  occurs. 

The  labia  interna  are  about  half  an  inch  broad  in  the  natural 
state,  and  do  not  project  obviously  beyond  the  labia  externa,  ex- 
cept in  cases  of  extreme  emaciation,  where  the  prominence  of 
the  latter  has  been  destroyed  by  a  removal  of  its  fat.  They 
are,  however,  very  subject,  as  the  individual  becomes  old,  to  a 
pointed  elongation,  increasing  their  breadth  to  an  inch,  or  an 
inch  and  a  half;  and  to  become  thickened  and  indurated.  A 
tribe  of  Hottentots,  the  Boschismans,  living  near  the  Cape  of 
Good  Hope,  are  uniformly  subject  to  this  enlargement;  which, 
for  a  long  time,  was  represented,  by  travellers,  as  an  organ  su- 
peradded  to  what  is  common  in  the  human  species. 


THE  VAGINA.  107 

The  Vestibulum  is  a  depression  of  twelve  or  fifteen  lines 
long,  between  the  labia  interna;  it  is  bounded  above  by  the  cli- 
toris, and  below  by  the  orifice  of  the  vagina.  It  is  abundantly 
furnished  with  mucous  lacunae. 

The  Urethra  of  the  female  has  its  external  orifice  (Orificium 
Urethra)  in  the  inferior  part  of  the  vestibulum,  about  one  inch 
below  the  glans  clitoridis,  and  is  generally  marked  by  a  slight 
rising,  which  is  easily  distinguished  by  the  sensation  of  touch 
alone;  its  margin  is  often  bounded  by  a  little  caruncle  on  each 
side.  The  urethra  itself  is  an  inch  long,  larger  and  much  more 
dilatable  than  that  of  the  male,  its  course  is  obliquely  down- 
wards and  forwards  from  the  neck  of  the  bladder;  passing  under 
the  symphysis  of  the  pubes,  and  being  slightly  curved  from  that 
cause.  It  consists  of  two  membranes,  a  lining  and  an  external 
one.  The  lining  membrane  is  a  continuation  of  that  of  the 
bladder;  it  is  thrown  into  several  longitudinal  folds,  and  has 
many  mucous  follicles  in  it.  The  external  coat  of  the  urethra 
consists  of  condensed  laminated  cellular  membrane,  having  a 
strong  affinity  with  muscular  fibre:  the  principal  direction  of 
the  fibres  is  transverse,  forming  a  cylindrical  body  of  half  an 
inch  in  its  transverse  diameter,  and  which  has  given  the  idea  of 
the  existence  of  a  prostate  gland  in  the  female:  the  lower  and 
lateral  surfaces  of  this  cylinder  are  in  contact  with  the  vagina, 
forming  a  protuberance  into  its  cavity;  and  the  upper  surface  is 
firmly  connected  to  the  triangular  ligament  of  the  pubes.  Im- 
mediately behind  the  neck  of  the  bladder,  we  find  the  vesical 
triangle  with  its  muscle,  as  in  the  male,  excepting  that  the  an- 
terior angle  of  it  goes  to  the  anterior  end  of  the  urethra. 

The  Fossa  Navicularis  is  that  portion  of  the  rima  vulvas 
which  is  below  the  vestibulum,  and  anterior  to  the  orifice  of 
the  vagina. 

SECT.  II. OF  THE  VAGINA. 

The  Vagina  is  a  thin  membranous  canal  which  leads  from  the 
vulva  to  the  uterus.  It  is  from  four  to  six  inches  in  length,  dif- 
fering according  to  age  and  pregnancy,  and  being  much  shorter 


108  ORGANS  OF  GENERATION. 

in  women  who  have  borne  children  than  in  virgins.  It  is  placed 
between  the  bladder  in  front,  and  the  rectum  behind,  being 
flattened  by  them  so  as  to  bring  its  anterior  and  posterior  sur- 
faces into  contact.  Its  anterior  extremity  is  the  smallest  of  the 
two;  and  presents  its  greatest  diameter  vertically,  while  that  of 
the  posterior  is  transverse.  As  it  follows  accurately  the  central 
line  of  the  pelvis,  it  is,  consequently,  curved  with  its  concavity 
forwards.  Its  anterior  parietes  are  shorter  than  the  posterior, 
both  from  the  smaller  depth  of  the  pelvis  in  this  direction,  and 
from  the  mode  of  connexion  with  the  uterus. 

The  vagina  is  formed  by  two  tunics;  a  fibrous  and  a  mucous 
one.  The  first  is  external,  of  a  light  red  colour,  highly  elastic, 
and  seems  to  consist  of  condensed  cellular  membrane,  the  fibres 
of  which  are  much  intermixed,  and  pass  in  every  direction.  It 
is  vascular,  and  immediately  adjacent  to  the  large  venous  sinuses 
of  the  pelvis.  The  mucous  membrane  being  a  continuation  of 
that  of  the  vulva,  is  at  and  near  its  anterior  orifice  of  a  vermi- 
lion tinge;  while,  posteriorly,  it  is  grayish  and  frequently 
spotted,  so  as  to  give  it  a  marbled  appearance:  its  thickness  di- 
minishes as  it  recedes  from  the  external  orifice;  and  upon  be- 
ing floated  in  water  many  mucous  lacunae  are  observable  upon  it. 
The  internal  surface  of  the  vagina  is  commonly  covered  with 
the  mucus  which  comes  from  its  lacunae.  On  the  anterior  or 
pubic  portion,  it  is  divided  longitudinally  by  a  middle  ridge, 
which  commences  by  a  sort  of  tubercle  just  below  the  orifice 
of  the  urethra,  and  proceeds  backwards,  becoming  indistinct  as 
it  approaches  the  uterus.  Transverse  ridges  formed  in  the  same 
way  by  folds  of  the  mucous  membrane,  arise  from  the  sides  of 
the  last  at  its  anterior  portion,  and  give  a  roughness  to  that  part 
of  the  vagina.  The  inferior  side,  or  that  next  to  the  rectum, 
has  the  same  kind  of  arrangement  of  the  mucous  membrane,  but 
not  so  distinct.  In  a  majority  of  subjects,  the  uterine  half  of 
the  vagina  is  perfectly  smooth,  but  the  rule  does  not  always 
hold. 

The  Corpus  Spongiosum  Vaginae  is  an  erectile  tissue,  like  that 
of  the  penis,  and  closely  resembles  in  structure  the  corpus 
spongiosum  urethras.  It  is  placed  at  the  anterior  end  of  the  va- 


THE  VAGINA.  109 

gina,  on  its  outer  circumference,  just  below  the  clitoris,  and  at 
the  base  of  the  labia  minora  or  interna.  It  is  an  inch  broad, 
and  a  line  or  two  thick,  adheres  closely  to  the  fibrous  coat  of  the 
vagina,  and  extends  around  the  superior  semi-circumference  of 
the  orifice,  but  not  around  the  inferior.  It  is  frequently  called 
Plexus  Retiformis. 

The  Sphincter  Vaginae  Muscle  surrounds  the  anterior  orifice 
of  the  vagina,  and  covers  the  plexus  retiformis.  It  is  about  an 
inch  and  a  quarter  wide,  and  arising  from  the  body  of  the  clito- 
ris and  the  crus  of  the  pubes,  behind  tbe  crus  of  the  clitoris, 
passes  backwards  and  downwards  to  be  inserted  into  the  dense, 
white  substance,  in  the  centre  of  the  perineum,  common  to  these 
muscles,  the  tranversi  perinei  and  the  anterior  point  of  the 
sphincter  ani.  There  is  a  strong  analogy  between  it  and  the 
accelerator  urinas  of  the  male. 

The  Transversus  Perinei  of  the  female,  has  the  same  circum- 
stances of  origin  and  insertion  as  in  the  male,  but  is  not  quite 
so  strong. 

On  each  side  of  the  orifice  of  the  vagina,  near  its  middle,  is 
frequently  found  a  mucous  gland,  the  size  of  a  garden  pea:  it 
corresponds  with  Couper's  gland  of  the  male  subject. 

The  Hymen,*  one  of  the  attributes  of  the  virgin  state,  is 
placed  at  the  anterior  orifice  of  the  vagina  for  the  purpose  of 
closing  it,  and  commonly  remains  until  it  is  ruptured  by  vio- 
lence. In  all  cases,  except  where  there  is  an  unnatural  adhesion, 
it  leaves  a  small  orifice  for  the  passage  of  mucus  and  of  men- 
strual blood.  In  my  own  observations,  I  have  found  it  most 
frequently  crescentic,  the  convexity  of  the  crescent  presenting 
downwards,  and  the  horns  upwards;  but  in  some  cases,  it  is  to 
one  side.  Next  in  frequency  to  the  lunated  is  the  circular  shape, 
where  it  surrounds  completely  the  orifice  and  leaves  a  hole  in 
its  own  centre.  There  are  some  other  varieties,  such  as  its  be- 
ing fleshy,  fasciculated,  unequally  divided  into  two  portions,  and 

*  J.  G.  Tolber.  Diss.  de  Variet.  Hymen.     Haller,  Icon.  Anat.  Fasc.  i.  Albin. 
Acad.  Annot.  Lib.  iv.     Santorini,  Septemd.  Tab. 
VOL.  II.  — 15 


110  ORGANS  OF  GENERATION. 

so  on,  which  are  narrated  by  different  writers.  Being  simply  a 
duplicature  of  the  mucous  membrane,  it  is  generally  so  weak  as 
to  be  ruptured  at  the  first  act  of  copulation,  or  even  from 
slighter  causes  during  infancy;  but  occasionally,  it  becomes 
thickened,  and  so  strong  as  to  require  division  with  the  knife. 
After  the  rupture  of  the  hymen,  its  place  is  indicated  in  subse- 
quent life  by  from  two  to  six  small  tubercles,  called  Carunculas 
My rti formes,  which  are  its  remains. 

The  peritoneum,  in  descending  from  the  uterus,  anteriorly, 
touches  the  top  of  the  vagina  for  a  little  distance,  and  is  then 
reflected  to  the  bladder,  but  posteriorly,  almost  the  upper  half 
of  the  vagina  has  a  peritoneal  coat  before  this  membrane  is  re- 
flected to  the  rectum.  The  attachment  of  the  vagina  to  the 
bladder  is  strong  and  close  just  about  the  urethra,  but  its  con- 
nexion with  the  rectum  is  by  rather  loose  cellular  substance. 


.SECT.  III.  —  OF  THE  UTERUS,  AND  ITS  APPENDAGES. 

The  Uterus,  or  Womb,  is  a  compressed  pyriform  body,  the 
larger  end  of  which  stands  upwards,  while  the  lower  is  directed 
downwards,  and  is  attached  to  the  vagina.  Unimpregnated,  it 
is  two  and  a  half  inches  long,  and  one  and  a  half  in  diameter  at 
its  widest  part.  The  posterior  face  is  very  convex,  while  the 
anterior  is  almost  flat,  or  very  slightly  convex.  It  is  about  one 
inch  in  thickness.  It  is  divided  by  anatomists  into  fundus, 
bodv>  and  neck.  The  fundus  is  formed  by  its  superior  ex- 
tremity, and  comprises  the  space  between  the  orifices  of  the 
Fallopian  tubes;  the  neck  is  the  lower  cylindrical  portion,  of 
about  an  inch  in  length;  and  the  body  is  the  part  intermediate 
to  the  two.  On  the  exterior  circumference  of  the  uterus  there 
are  no  marks  or  lines  distinguishing  these  several  portions  from 
each  other. 

The  uterus,  being  destined  to  lodge  the  foetus  from  a  short 
period  after  conception  to  the  moment  of  birth,  has  a  cavity 
ready  for  its  reception.  The  shape  of  this  cavity  bears  some 
general,  but  not  a  rigid  resemblance  to  that  of  the  organ  itself, 
and  is  so  much  flattened  as  to  have  its  anterior,  and  posterior 
parietes  in  contact,  or  nearly  so.  The  cavity  of  the  body  is  an 
equilateral  triangle  of  eight  or  ten  lines  in  diameter;  the  sides 


UTERUS,  AND  ITS  APPENDAGES.  Ill 

of  the  triangle  are  bent  inwards  in  parabolic  curves,  in  such  a 
way  as  to  present  their  convexities  to  the  cavity  of  the  uterus: 
this,  of  course,  occasions  an  apparent  elongation  of  the  angles. 
The  inferior  angle  is  continued  into  the  cavity  of  the  neck, 
while  the  two  superior  run  into  their  respective  Fallopian  tubes. 
From  this  arrangement  it  happens  that  the  parietes  of  the  uterus 
are  only  two  or  three  "lines  thick  on  the  angles  of  the  triangular 
cavity,  while  at  the  middle  they  are  from  four  to  six  lines.  The 
cavity  of  the  neck  has  not  its  anterior  and  posterior  sides  so 
near  together  as  that  of  the  body;  and  is  rather  cylindrical, 
being  smaller,  however,  at  the  upper  and  lower  ends  than  in 
the  middle.  This  arrangement  gives  to  its  sides  a  paraboloid 
curvature  which  presents  its  convexity  outwards,  differing  in 
that  respect  from  the  corresponding  curvature  in  the  cavity  of 
the  body. 

The  cavity  of  the  neck  terminates  in  the  vagina  by  an  orifice 
about  the  size  of  a  small  writing-quill,  but  ovoidal,  and  pre- 
senting its  long  diameter  transversely.  This  orifice  i*  the  Os 
Tineas,  or  Orificium  Externum  Uteri;  frequently,  without  ap- 
parent disease,  I  have  seen  it  conoidal,  with  its  base,  half  an  inch 
in  diameter,  presenting  downwards.  The  upper  orifice,  where- 
by the  cavity  of  the  neck  communicates  with  that  of  the  body, 
is  not  subject  to  such  fluctuations  in  size:  it  is  occasionally  called 
Orificium  Internum  Uteri,  and  is  generally  somewhat  larger 
than  a  small  writing-quill.  The  os  tincse  is  bounded  before  and 
behind  by  the  lips  of  the  uterus,  formed  by  the  projection  of 
the  neck  into  the  vagina.  For  the  most  part  the  anterior  side 
of  the  vagina  is  directly  continuous  with  the  anterior  lip;  so 
that  its  projection  is  very  inconsiderable,  and,  indeed,  not  ap- 
preciable to  the  finger:  at  the  same  time,  this  lip  is  rather  thicker 
than  the  posterior.  The  projection  of  the  latter,  on  the  contrary, 
is  always  well  marked,  because  the  vagina,  instead  of  being 
inserted  into  its  ridge,  is  joined  to  the  posterior  surface  of  its 
base. 

The  cavity  of  the  uterus  is  lined  by  a  very  thin  mucous  mem- 
brane, a  continuation  of  that  of  the  vagina.  This  membrane  is 
of  a  light  pink  colour,  which  changes  to  a  vermilion  during  the 
period  of  menstruation;  it  is  furnished  with  villosities,  which, 
though  seen  with  difficulty  in  the  usual  way,  may  be  rendered 


112  ORGANS  OF  GENERATION. 

apparent,  by  floating  the  uterus  in  water;  and  it  adheres  so 
closely  to  the  substance  of  the  uterus,  that  it  seems  to  form  an 
inseparable  portion  of  it,  which  can  neither  be  dissected  nor  ma- 
cerated off  entirely,  as  in  the  case  of  other  mucous  membranes. 
This  membrane  is  smoothly  laid  upon  the  cavity  of  the  body, 
and  gives  it  a  polished  shining  surface.  On  the  cavity  of  the 
neck,  it  is  wrinkled  along  the  anterior  and  the  posterior  parts; 
there  being  a  longitudinal  line  running  along  the  centre,  and  on 
each  side  of  this  line  transverse  or  oblique  elevations  or  dupli- 
catures.  This  arrangement  presents  an  arborescent  appearance, 
technically  called  the  arbor  vitae.  In  the  interstices  of  these 
duplicatures  there  are  some  small  mucous  glands  or  lacunae, 
which,  as  their  orifices  are  exposed  to  obliteration  from  inflam- 
mation or  some  other  irritation,  become  distended  into  small 
spherical  sacs  by  the  accumulation  of  their  habitual  secretion. 
Naboth,  from  seeing  them  in  this  state,  mistook  them  for  eggs, 
or  the  rudiments  of  the  foetus,  and  the  error  has  been  comme- 
morated by  their  being  called  Ovula  Nabothi. 

The  uterus  is  covered  completely  by  the  peritoneum;  in  the 
reflection  of  the  latter,  from  the  rectum  to  the  bladder,  it  ad- 
heres to  the  uterus  by  a  subjacent  cellular  substance,  which  al- 
lows it  to  be  dissected  off  without  difficulty.  The  same  dupli- 
cature  of  peritoneum  which  encloses  the  uterus,  is  also  reflected 
from  each  of  its  lateral  margins,  by  their  whole  length,  to  the 
corresponding  side  of  the  lesser  pelvis,  and  forms  the  Lateral 
or  the  Broad  Ligament,  (Ligament  a  Later  alia,  Lala.)  The 
peritoneum,  in  passing  from  the  uterus  forwards  to  the  bladder, 
forms,  on  each  side,  a  duplicature,  not  very  distinct,  and  de- 
pending, in  a  measure,  upon  the  state  of  the  bladder;  this  con- 
stitutes the  Anterior  Ligament.  The  same  membrane,  in 
passing  from  the  back  of  the  uterus  to  the  rectum,  and  in  co- 
vering the  posterior  superior  end  of  the  vagina,  also  forms,  on 
each  side,  a  duplicature,  denominated  the  Posterior  Ligament; 
they  are  always  better  seen  than  the  anterior.  Muscular  fibres 
are  said  to  be  found,  occasionally,  between  the  laminae  of  these 
several  duplicatures,  running  in  the  direction  of  the  latter:* 

*  J.  F.  Meckel,  vol.  ii.  p.  605. 


UTERUS,  AND  ITS  APPENDAGES.  113 

they  have  not  been  presented  to  me  in  such  a  way  as  to  arrest 
my  attention. 

The  broad  ligaments,  along  with  the  uterus,  form  a  transverse 
septum,  passing  from  one  side  of  the  pelvis  to  the  other;  and 
contain,  between  their  laminae,  the  arteries  and  the  veins  which 
belong  to  the  uterus  and  ovaries. 

Besides  the  duplicatures  of  peritoneum,  the  uterus  is  retained 
in  its  position  by  the  Ligamenta  Rotunda,  one  on  each  side. 
These  round  ligaments  arise  from  the  sides  of  the  uterus,  a  lit- 
tle below  the  insertion  of  the  Fallopian  tubes,  and  going  between 
the  laminae  of  the  broad  ligament,  reach,  finally,  the  internal 
abdominal  ring:  they  then  traverse  the  abdominal  canal  and  the 
external  ring  after  the  manner  precisely  of  the  spermatic  chord, 
and  terminate  by  several  fasciculi  in  the  fatty  cellular  matter  of 
the  rnons  veneris  and  of  the  labia  majora.  The  round  ligaments  are 
rather  smaller  in  the  middle  than  at  either  extremity:  they  con- 
sist of  a  condensed  cellular  or  fibrous  structure,  and  have  many 
blood  vessels  in  them.  It  has  been  asserted,*  that  they  con- 
tain strongly  marked  muscular  fibres;  some  of  which  come  from 
the  uterus,  and  others  from  the  broad  muscles  of  the  abdomen. 
No  evidence  of  this  fact  has  as  yet  been  presented  to  me,  though 
I  do  not  deny  it;  and,  indeed,  I  think  it  probable,  that  such 
fibres  may  be  developed  there  during  gestation. 

The  texture  of  the  uterus  is  very  compact,  and  of  a  cartila- 
ginous feel;  it  is  composed  of  fibrous  matter,  intermixed  with 
a  great  many  blood  vessels.  In  regard  to  its  fibrous  structure, 
there  is  no  subject  in  anatomy  on  which  opinions  are  more  di- 
vided, or  more  authoritative  and  numerous  on  both  sides  of 
the  question.  Some  deny  its  existence  at  any  period,  while 
others  admit  it  as  a  constant  condition:  others,  again,  limit  its 
duration  only  to  the  period  of  pregnancy.  Without  dwelling 
on  the  value  of  the  several  doctrines,  and  the  means  and  obser- 
vations tending  to  support  them,  it  may  be  sufficient  here  to 
mention  that  the  structure  of  the  uterus  takes  on  very  impor- 
tant and  strongly  marked  changes,  in  passing  from  the  unim- 
pregnated  state  to  that  of  advanced  gestation.  In  the  first  the 
fibres  look  ligamentous  and  pass  in  every  direction,  but  so  as  to 

*  J.  F.  Meckel,  loc.  cit. 


114  tfRGANS  OP  GENERATION. 

permit  the  uterus  to  be  lacerated  more  readily  from  the  cir- 
cumference to  the  centre  than  in  any  other  course:  it,  indeed, 
manifests  an  indisposition  to  be  torn  in  a  laminated  manner. 
The  fibres,  moreover,  break  off  short,  are  separated  by  the  blood 
vessels,  and  seem  to  contain,  in  their  interstices,  something  like 
fibrine. 

In  the  impregnated  state,  on  the  contrary,  the  vessels  become 
immensely  increased  in  size,  the  laminated  structure  becomes 
very  evident,  and  submits  readily  to  the  tearing  of  one  layer 
from  the  other:  these  lamina  consist  of  fibres,  which  are  princi- 
pally parallel  with  each  other.  The  muscular  nature  of  these 
fibres  seems  to  be  sufficiently  proved,  by  their  powerful  con- 
traction in  the  expulsion  of  the  foetus,  and  on  being  irritated  by 
the  introduction  of  the  hand.  They  are,  however,  not  red  like 
other  muscles,  but  of  a  very  light  colour  as  those  of  the  bladder 
and  intestines;  and  are  collected  into  fasciculi  of  peculiar  flatness 
and  looseness.  The  development  of  this  muscular  structure  is 
not,  however,  limited  to  the  pregnant  state,  but  it  is  disposed  to 
manifest  itself  on  all  occasions  which  produce  an  increased  size 
in  the  uterus.  This  fact  was  first  excmplied  to  me  in  a  small 
scirrhus  of  a  virgin  uterus,  presented  by  Dr.  Hugh  L.  Hodge,* 
and  has  been  still  farther  confirmed  in  a  case,  where  the  scirrhus 
was  five  or  six  inches  in  diameter;  also  in  a  virgin  uterus,  very 
much  enlarged  from  scirrhus,  presented  by  Dr.  Charles  D. 
Meigs.  A  similar  fact  has  been  noticed  by  Lobstein,  of  Stras- 
burg,  where  the  tumour  was  also  steatomatous. 

The  fibres  of  the  uterus,  examined  near  the  term  of  pregnan- 
cy, consist  in  two  planes  separated  by  the  large  blood  vessels; 
one  within  and  the  other  without.  These  layers  are  readily 
divisible  into  subordinate  laminae,  intermixed  with  one  another, 
but  yet  to  a  considerable  extent  separable.  The  external  layer 
is  thicker  than  the  internal,  and  both  have  an  increased  thick- 
ness at  the  fundus;  while  they  are  much  diminished,  and  in- 
deed indistinct,  at  the  cervix. 

The  fibres  generally  are  either  circular  or  longitudinal,  but 
many  of  them  are  oblique.  The  exterior  surface  of  the  exter- 
nal plane,  is  composed  principally  of  longitudinal  fibres,  within 

*  Now  Professor  of  Midwifery  in  the  University  of  Pennsylvania. 


UTERUS,'AND  ITS  APPENDAGES.  115 

which  are  the  circular.  The  inner  plane,  on  the  contrary,  has 
the  circular  fibres  external,  and  the  longitudinal  internal.  In 
both  planes  the  circular  fibres  are  more  abundant  at  the  fundus, 
.and  the  longitudinal  upon  the  body  of  the  uterus;  but,  generally 
speaking,  there  are  collectively  more  longitudinal  than  circular 
fibres. 

Of  the  Fallopian  Tubes. 

The  Fallopian  tubes  ( Tubas  Fallopianae)  are  two  membranous 
canals,  one  on  either  side,  fixed  in  the  superior  margin  of  the 
broad  ligaments  of  the  uterus.  They  serve  to  conduct  the  ru- 
diments of  the  embryo  from  the  ovarium  into  the  uterus.  They 
are  about  four  inches  long,  and  extend  from  the  upper  angle  of 
the  uterine  cavity  to  the  side  of  the  pelvis:  their  outer  extre- 
mity is  loose,  and  hangs  upon  the  posterior  face  of  the  broad 
ligament  over  the  ovarium,  consequently,  inclines  downwards, 
thereby  forming  an  angle  with  the  other  portion. 

At  their  uterine  extremities  the  Fallopian  tubes  are  about  the 
size  of  the  vas  deferens,  resemble  it  strongly,  and  scarcely  ad- 
mit a  hog's  bristle;  but  having  proceeded  about  one-half  of  their 
length,  they  begin  to  enlarge,  and  continue  to  do  so  rapidly  for 
an  inch,  until  they  reach  the  size  of  a  writing-quill;  they  then 
contract  again  somewhat,  and  immediately  afterwards  expand 
into  a  broad  trumpet-shaped  mouth.  The  latter  has  an  oblique 
orifice,  the  edge  of  which  is  extremely  irregular,  by  being  re- 
solved into  a  number  of  ragged  fringe-like  processes,  of  unequal 
size  and  length;  and  which,  as  a  whole,  are  called  Corpus  Fim- 
briatum  or  Morsus  Diaboli.  One  of  the  longest  of  these  pro- 
cesses adheres  to  the  external  end  of  the  ovarium. 

The  Fallopian  tube  is  covered  by  the  peritoneum,  and  con- 
sists of  two  coats:  the  external  is  fibrous,  and  bears  sufficient 
resemblance  to  the  structure  of  the  uterus  to  be  considered  a 
continuation  of  it;  the  internal  is  mucous,  and  is  likewise  a  con- 
tinuation of  the  corresponding  one  of  the  uterus.  The  external 
end  of  the  tube,  which  is  called  Pavilion  by  the  French  anato- 
mists, is  flaccid,  thin,  and  generally  in  a  collapsed  state,  as  it  is 
formed  solely  by,  the  mucous  membrane,  assisted  by  the  peri- 
toneum, neither  of  which  furnishes  resistance  sufficient  to  keep 


116  ORGANS  OP  GENERATION. 

it  expanded;  but,  as  many  blood  vessels  enter  into  its  composi- 
tion, their  turgescence,  in  sexual  excitement,  probably  commu- 
nicates a  certain  degree  of  erection. 


Of  the.  Ovaries. 

The  Ovaries,  (Ovaria,  Testes  Muliebres,}  two  in  number, 
one  on  either  side,  are  situated  on  the  posterior  face  of  the  broad 
ligaments,  by  a  duplicature  of  which  they  are  surrounded,  and 
are  twelve  or  fifteen  lines  below  the  Fallopian  tubes.  Their 
shape  is  that  of  a  compressed  ovoid,  about  half  the  size  of  the 
male  testicle;  their  long  diameter  is  horizontal;  they  are  sus- 
pended from  the  broad  ligament  rather  by  the  edge  than  by  the 
flat  surface,  so  that  they  project,  and  are  to  a  considerable  de- 
gree pendulous.  Their  distance  from  the  uterus  varies  from 
an  inch  to  an  inch  and  a  half,  and  from  the  internal  end  of  each 
one,  there  proceeds  a  small  vascular  fibrous  chord,  the  Liga- 
ment of  the  Ovarium,  which  is  inserted  into  the  uterus,  some- 
what below  the  origin  of  the  Fallopian  tube.  * 

From  their  being  the  seat  of  conception,  they  have,  in  the 
youthful  and  healthy  female,  a  pliancy  and  succulency,  indi- 
cative of  their  state  of  preparation  for  the  act;  but  in  advanced 
life  they  diminish  much  in  volume  and  becpm'e  hard  and  dry. 
Their  surface,  originally  smooth  or  slightly  embossed,  is  sub- 
sequently rendered  uneven,  by  repeated  acts  of  conception, 
leaving  on  it  a  number  of  cicatrices  or  small  stellated  fis- 
sures. 

They  are  of  a  light  pink  colour.  Within  the  peritoneal  coat 
is  another,  the  Tunica  Albuginea,  of  a  strong,  compact,  fibrous 
texture,  like  the  same  coat  of  the  testicle,  and  sending  inwards 
many  processes. 

The  structure  of  the  ovarium  is  not  ascertained  with  entire 
satisfaction,  though  the  grosser  arrangement  of  it  is  known. 
But  few  females,  of  such  as  are  presented  in  our  dissecting 
rooms,  have  these  parts  ^in  a  state  fit  for  study,  owing  to  age, 
disease,  or  excessive  sexual  indulgence:  my  best  opportuni- 
ties have  been  derived  from  post  mortem  examinations,  in  pri- 
vate, of  individuals  of  from  fourteen  to  twenty,  where  the  virgin 
state  had  been  preserved.  When  an  ovarium  of  the  latter  kind 


THE  OVARIES.  117 

can  be  got,  by  cutting  through  the  tunica  albuginea  simply,  and 
then  tearing  open  the  organ,  it  will  be  found  to  consist  of  a 
spongy  tissue,  abundantly  furnished  with  blood  vessels  from 
the  spermatic  artery  and  vein.  In  this  spongy  tissue  are  from 
fifteen  to  twenty  spherical  vesicles  (Qvula  Graafiana)  varying 
in  size  from  half  a  line  to  three  lines  in  diameter;  the  larger 
ones  are  nearer  the  surface,  and  from  having  caused  the  absorp- 
tion of  the  tunica  albuginea,  may  sometimes  be  seen  through 
the  peritoneal  coat,  and  give  to  the  surface  of  the  ovarium  its 
embossed  condition.  The  vesicles  contain  a  transparent  fluid 
supposed  to  be,  or  to  have  within  it,  the  rudiments  of  the  em- 
bryo. As  the  vesicles  are  evolved  they  advance  from  the  centre 
to  the  circumference.  Their  parietes  are  thin,  transparent, 
and  have  creeping  through  them  minute  arterial  and  venous 
ramifications.* 

The  Organs  of  Generation  in  the  female  are  supplied  with 
blood  principally  from  the  internal  pudic  and  other  branches 
of  the  hypogastric  artery:  their  veins  run  into  the  hypogastric. 
Their  nerves  come  from  the  sacral  and  from  the  hypogastric 
plexus. 

The  Bladder  and  the  Rectum,  with  unimportant  exceptions, 
are  the  same  in  both  sexes.  The  Levator  Ani,  the  Coccygeus, 
and  the  Sphincter  Ani,  are  also  similar.  The  pelvic  aponeu- 
rosis  in  the  female,  besides  connecting  the  bladder  to  the  sides 
of  the  pelvis,  is  attached  to  the  anterior  part  of  the  vagina.  The 
triangular  ligament  of  the  urethra  also  exists,  but  under  circum- 
stances somewhat  modified  by  the  close  connexion  of  the  urethra 
with  the  vagina. 


*  In  an  ovary  exhibited  to  me  by  Dr.  Hopkinson,  there  were  thirty-six  ve- 
sicles. 


VOL.  II.— 16 


118  ORGANS  OP  GENERATION. 

CHAPTER  III. 

OF  THE  LACTIFEROUS  GLANDS,  OR  BREASTS. 

THE  Breasts  (Mammas)  of  the  female,  are  intended  for  the 
secretion  of  milk,  and  thereby  to  maintain  the  connexion  be- 
tween mother  and  infant,  for  some  time  after  the  uterine  life  of 
the  latter  is  passed.  All  mammiferous  animals  exercise  this 
function:  in  birds  there  is  a  sort  of  substitute  for  it,  in  the 
changes  which  take  place  in  the  first  stomach  or  crop  during 
incubation.  In  the  male  subject,  there  is,  also,  a  small  glandular 
body  on  each  side,  which  has  the  same  organization  as  in  the 
female,  but  is  in  miniature,  and  always  remains  in  a  collapsed 
state,  with  some  rare  exceptions,  when  it  has  been  known  to 
expand  in  volume,  and  to  furnish  a  secretion,  as  in  the  female.* 

The  Breasts  are  two  in  number,  one  on  either  side;  they  are 
situated  on  the  same  level,  in  front  of  the  pectoralis  major  mus- 
cle, and  between  the  arm-pit  and  the  sternum.  They  are  he- 
mispherical, and  have  their  base  united  to  the  muscle  by  a  thin 
lamina  of  loose,  extensible,  cellular  substance,  containing,  even 
in  corpulent  women,  but  little  fat.  The  skin  which  covers  the 
front  of  this  gland  is  very  fine  and  thin,  so  that  the  blood  which 
circulates  in  its  veins  may  be  readily  seen.  Between  the  skin 
and  the  front  surface  of  the  gland,  there  is  a  considerable  thick- 
ness of  cellular  adipose  matter,  which,  from  its  superabundance 

*  In  a  male  patient,  now  resident  in  the  Philadelphia  Alms  House,  the  pheno- 
menon of  a  full  evolution  of  the  glandular  structure  in  both  breasts  is  manifested. 
The  individual  (James  Mclntyre)  is  forty-five  years  of  age,  the  breasts  are  as  large 
as  those  of  a  nursing  woman,  but  the  nipples  are  not  proportionately  evolved. 
Though  his  frame  is  robust,  and  well  set,  the  voice  is  feminine ;  his  external  or- 
gans of  generation  are  about  the  size  of  those  of  a  boy  of  fourteen  or  fifteen. 
Thinking  that  there  might  be  an  internal  state  approaching  to  hermaphrodism,  he 
informed  me,  on  inquiring,  that  in  earlier  .life  lie  had  the  common  inclinations  for 
the  female.  He  also  informed  me  that  this  unusual  development  took  place  seven 
or  eight  years  ago,  owing  to  an  excessive  salivation;  but  as  he  has  a  reserve  on  the 
subject,  this  statement  may,  probably,  be  received  with  some  qualifications.  I 
have  also  seen  a  second  case,  in  which  the  voice  is  weak  and  .feminine,  but  the 
genital  organs  have  not  been  examined. — July,  1826. 


LACTIFEROUS  GLANDS.  119 

in  certain  individuals,  gives  to  them  an  appearance  of  having 
the  glands  enormously  enlarged.  There  is,  however,  a  great 
variety  in  the  size  of  the  glandular  structure  itself;  for  in  fe- 
males who  are  youthful  and  giving  suck,  they  are  much  larger 
than  in  such  as  have  passed  the  period  of  child-bearing,  and 
whose  health  is  impaired.  When  all  the  fatty  matter  has  been 
removed  from  a  breast,  and  it  is  permitted  to  repose  upon  a  ta- 
ble, its  hemispherical  shape  disappears,  and  it  then  seems  rather 
a  flattened  circular  disk,  of  from  four  to  five  inches  in  diameter. 

The  mamma  is  of  a  very  light  pink  colour;  and  though  very 
flaccid  and  yielding  on  being  handled,  its  texture  is  actually  ex- 
tremely tough,  and  is  cut  only  by  much  force.  With  the  ex- 
ception of  bone,  it  dulls  the  knife  sooner  than  any  other  tissue 
of  the  body.  Its  grosser  arrangement  consists  in  lobes  of  dif- 
ferent sizes,  united  in  such  a  way  by  cellular  texture,  that,  though 
they  can  be  pulled  somewhat  apart,  they  cannot  be  entirely  se- 
parated without  injury.  These  lobes,  when  examined  through 
the  skin,  give  to  the  gland  a  knotted  feel,  and  are  sometimes 
partially  affected  by  inflammation,  so  as  to  become  still  more 
distinct.  The  Lobes  are  composed  of  Lobuli,  which  are  resol- 
vable by  maceration  and  particular  modes  of  treatment,  into 
small  graniform  masses  (acini)  about  the  size  of  millet  seed, 
and  which  contain  the  ultimate  glandular  arrangement.  The 
acini  themselves  consist  of  very  small  oblong  vesicles,  united 
by  cellular  substance,  and  by  the  common  blood  vesels;  and  are 
said  to  be  very  apparent  by  the  aid  of  a  microscope  in  a  lac- 
tescent gland.* 

Excretory  Ducts  (Ductus  Galactophori,  Lactiferi]  of  this 
gland  are  numerous.f  They  are  of  an  arborescent  shape,  and  be- 
gin by  very  fine  extremities  or  ramuscles  in  the  acini ;  the  ramus- 
cles  from  several  acini  coalesce  into  a  larger  branch;  several 
branches  unite  to  form  one  still  larger,  and  so  on,  successively, 
until  a  lactiferous  duct,  constituting,  as  it  were,  the  body  of  the 
tree,  is  formed  by  this  assemblage.  These  trunks  vary  considera- 
bly in  size,  according  to  the  number  of  tributary  branches,  and 
having  got  towards  the  centre  of  the  gland  near  the  nipple,  from 

*  Marjolin,  Manual  D'Anat.     J.  F.  Meckel,  Manual  D'Anat. 
f  Alex.  Kolpin,  Dfss.  Inaug.  de  Struct.  Mam.     Cuboli,  Append,  ad  Septemd. 
Tab.  Santorini.     Girardi,  Append,  ad  Septemd.  Tab.  Santorini. 


120  ORGANS  OF  GENERATION. 

two  to  four  of  them,  according  to  Cuboli,  run  into  a  common  stock 
or  root,  called  a  Lactiferous  Sinus.  These  Sinuses  are  in  all  about 
fifteen:  they  are  only  a  few  lines  long,  and  differ  in  size;  some  not 
being  larger  than  a  lactiferous  duct,  while  others  have  a  diameter 
of  from  two  to  three  lines.  The  sinus  at  the  end  next  to  the  nipple 
terminates  in  a  sort  of  rounded  cul-de-sac;  but  from  the  extremity 
of  the  sac  a  conoidal  tube  arises  which  runs  through  the  nipple, 
and  conducts  the  milk:  the  point  of  this  tube  is  very  fine,  and 
ends  on  the  top  of  the  nipple.  This  tube,  from  its  shape,  is  suited 
to  the  retention  of  milk;  in  addition  to  which,  it  is  sometimes 
dilated  in  the  middle,  is  curved  when  the  nipple  is  not  in  a  state 
of  erection  or  stretched  out,  and  terminates  by  an  external  ori- 
fice, which  is  so  small  as  to  be  seen  with  difficulty  by  the  naked 
eye. 

The  excretory  ducts  of  the  breast,  under  which  term  may  be 
comprehended  the  lactiferous  -ducts,  the  sinuses,  and  the  conoi- 
dal tubes  in  the  nipple,  are  formed  by  a  soft,  thin,  and  semi-trans- 
parent membrane,  very  capable  of  extension  and  of  contraction. 
The  trunks  generally  go  deeply  through  the  substance  of  the 
gland,  and  are  tortuous,  but  do  not  anastomose  laterally  with 
one  another;  whence  it  happens  that  the  lobes  and  lobules  of 
the  gland  are  arranged  into  sections,  each  of  which  has  its  ap- 
propriate excretory  duct.  In  order  to  make  a  complete  injec- 
tion of  the  gland,  each  sinus  must  be  separately  injected  through 
its  conoidal  tube.  This  rule  is  not,  however,  of  universal  ap- 
plication, as  in  some  experiments  performed  by  the  elder  Meckel 
upon  women  advanced  in  pregnancy  and  during  lactation,  he 
succeeded  in  forcing  mercury  through  one  sinus,  by  its  ramifi- 
cations, into  those  of  another :  this  route  was  supposed  to  have 
.been  through  the  finest  extremities  of  the  ducts.  The  whole 
gland  itself  may,  however,  from  the  infrequency  of  this  circum- 
stance, and  from  the  difficulties  and  partial  condition  of  these 
anastomoses,  rather  be  considered  as  a  congeries  of  smaller 
glands  kept  distinct  by  the  interposition  of  cellular  substance  be- 
tween their  lobes ;  but  joined,  in  one  respect,  by  having  the  ter- 
minations of  their  excretory  tubes  collected  into  one  bunch  in 
the  nipple.  This  latter  circumstance  seems  to  be  only  a  provi- 
sion for  the  more  convenient  sucking  of  the  infant. 


LACTIFEROUS  GLANDS.  121 

The  excretory  ducts  are  no  where  furnished  with  valves, 
which  accounts  for  the  facility  with  whfch  they  may  be  injected 
backwards  from  the  nipple.  An  opinion  was  entertained  by 
Haller,  and  by  other  anatomists  after  him,  that  some  of  these 
ducts  originated  in  the  surrounding  cellular  substance,  but  this 
has  been  refuted  by  the  researches  of  Cuboli.  Some,  anatomists 
have  thought  that  there  is  a  direct  communication  between  the 
ends  of  the  lactiferous  tubes  and  the  arteries,  veins,  and  lym- 
phatics. Mascagni,  after  a  very  successful  injection  of  the  gland, 
whereby  its  vesicles  were  filled  with  quicksilver,  not  meeting 
with  such  an  occurrence,  was  induced  to  think  that  when  the 
communication  did  happen,  it  was  produced  by  rupture. 

The  Areoldj 

In  virgins  is  a  rose-coloured  circle,  which  surrounds  the  base 
of  the  papilla  or  nipple.  In  women  who  have  borne  children, 
or  in  those  whose  age  is  advanced,  it  becomes  of  a  dark  brown. 
The  skin  of  the  areola  is  extremely  delicate,  and  on  its  surface, 
particularly  in  pregnant  or  nursing  females,  there  are  from  four 
to  ten  tubercles,  which  sometimes  form  a  regular  circle  near  its 
circumference,  and  in  other  subjects  are  irregularly  distributed. 
Each  of  these  tubercles  has  near  its  summit  three  or  four  fora- 
mina, which  are  the  orifices  of  the  excretory  ducts  of  a  little 
gland  forming  the  tubercle.  The  areola  consists  of  a  spongy 
tissue  beneath  which  there  is  no  fat;  it  is  susceptible  of  disten- 
tion  during  lactation,  or  from  particular  excitement. 

The  greater  number  of  anatomists  have  considered  these  tu-. 
bercles  as  intended  only  for  the  secretion  of  an  unctuous  fluid 
which  lubricates  the  areola  and  nipple,  and  protects  them  from 
excoriation  by  the  sucking  of  the  infant.  It  is  said,  however,* 
that  when  some  time  has  elapsed  after  a  repast,  or  when  there 
has  been  a  long  interval  to  the  nursing  of  the  child,  milk  flows 
from  them  abundantly;  but  that  in  inverse  circumstances  a 
transparent,  limpid  fluid  is  distilled  in  small  drops :  all  of  which 
would  tend  to  prove  that  they  are  of  the  same  nature  with  the 

*  J.  F.  Meckel, 


122  ORGANS  OF  GENERATION. 

mammas  themselves,  being  only  smaller.  In  addition  to  them, 
it  is  said,  that  the  areola  and  the  nipple  are  furnished  with  a 
great  number  of  sebaceous  glands,  which  do  not  elevate  them- 
selves above  the  surface,  and  which  may  be  found  on  and  near 
the  tubercles. 

The  Papilla, 

Is  the  truncated  cone  in  the  centre  of  the  mamma,  of  the  same 
colour  with  the  areola,  and  surrounded  by  it.  The  lactiferous 
tubes  terminate  on  its  extremity.  It  is  collapsed  and  in  a  very 
pliable  state  for  the  most  part,  but  when  excited  it  swells,  be- 
comes more  prominent,  and  of  a  deeper  colour.  Its  skin  is 
rough,  and  provided  with  numerous  and  very  small  papillae. 
Its  internal  structure  consists  of  the  extremities  of  the  lactiferous 
tubes  united  by  condensed  cellular  membrane. 

The  mamma  is  supplied  with  blood  from  the  external  thoracic, 
intercostal,  and  the  internal  mammary  arteries.  Its  veins  attend 
their  respective  arteries.  The  nerves  come  from  the  axillary 
plexus  and  from  the  intercostals.  The  lymphatics  run  into  the 
internal  mammary,  intercostal,  and  axillary  trunks. 


BOOK  VII. 


Of  the  Organs  of  Respiration. 

THE  Organs  of  Respiration  are  the  Larynx,  the  Trachea, 
and  the  Lungs. 


CHAPTER  I. 

OF  THE  LARYNX. 

The  Larynx  is  an  irregular  cartilaginous  tube  that  forms  the 
upper  extremity  of  the  windpipe.  It  is  situated  immediately  be- 
low the  os  hyoides  and  the  root  of  the  tongue,  where  it  may  be 
felt  readily  through  the  integuments,  and  by  its  prominence  con- 
tributes to  the  outline  of  the  neck.  Its  position  is  such,  that  it  is 
bounded  behind  by  the  pharynx,  which  is  interposed  between  it 
and  the  vertebrae  of  the  neck ;  and  laterally  by  the  primitive  ca- 
rotid arteries  and  the  internal  jugular  veins.  It  gives  passage 
to  the  air  which  is  inhaled  into  the  lungs  or  exhaled  from  them, 
and  also  contributes  essentially  to  the  production  of  the  voice. 
Its  special  use,  on  the  latter  occasion,  has  induced  some  anato- 
mists to  give  it  a  description  apart  from  that  of  the  other  organs 
of  respiration ;  but  as  the  function  of  voice  is  subordinate  to  that 
of  respiration,  I  have  preferred  an  observance  of  its  most  natu- 
ral and  local  connexions. 

Five  distinct  cartilages  form  the  skeleton  of  this  structure :  the 


124  ORGANS  OP  RI£PIRATIOi\. 

os  hyoides,  which  is  common  to  it  and  to  the  root  of  the  tongue, 
also  contributes  to  its  superior  part,  in  a  manner  which  will  be 
presently  mentioned.  The  cartilages  are  one  Thyroid,  one  Cri- 
coid,  one  Epiglottis,  and  two  Arytenoid. 

The  Thyroid  Cartilage  (Cartilago  Thyroidea)  is  the  largest  of 
the  five,  and  being  placed  about  one  inch  below  the  os  hyoides, 
produces  in  the  upper  part  of  the  neck  the  prominence  called 
Pomum  Adami.  It  consists  in  two  lateral  halves,  which  in 
most  individuals  are  perfectly  symmetrical,  and  are  continuous 
with  each  other  on  the  middle  line  of  the  body.  These  tw* 
sides  form  at  their  line  of  junction  an  angle  projecting  forwards, 
and  resembling  that  of  the  canal  or  hydraulic  gate :  the  superior 
part  of  the  angle  is  more  prominent  than  the  inferior;  particu- 
larly in  the  male  subject.  The  sides  pf  this  body  lean  outwards, 
by  which  its  transverse  diameter  above  is  increased. 

The  angle  is  terminated  above  by  a  deep  notch,  from  which 
the  superior  margin  begins  to  form  a  curvature,  on  either  side, 
like  the  letter  S ;  the  inferior  margin  is  also  somewhat  curvefl, 
but  to  a  smaller  degree.  The  posterior  margin  of  each  half  is 
nearly  straight,  but  is  elongated  above,  with  the  aid  of  the  upper 
margin,  into  a  long  process,  the  Cornu  Majus;  and  below  with 
the  aid  of  the  inferior  margin,  into  another  process  not  so  long, 
Cornu  Minus.  By  the  latter,  the  thyroid  cartilage  is  articulated 
by  ligamentous  fibres  called  the  lateral  crico-thyroid  ligament,  to 
the  side  of  the  cricoid  cartilage,  which  thereby  becomes  the  ful- 
crum of  many  of  its  motions. 

The  internal  surface  of  each  half  of  the  thyroid  cartilage  is 
flat;  but  the  exterior  surface  is  slightly  marked  by  the  sterno- 
thyroid  and  the  thyreo-hyoid  muscles. 

The  Cricoid  Cartilage  (Cartilago  Cricoidea]  is  placed  below 
the  thyroid,  and  is  the  base  of  the  larynx.  It  is  an  oval  ring,  of 
an  unequal  thickness  and  breadth. 

Its  inferior  margin  is  nearly  straight  and  horizontal,  and  is 
connected  to  the  first  ring  of  the  trachea;  it  is  also  thinner  than 
the  superior:  the  latter  is  very  oblique,  and  rises  from  before 
backwards  and  upwards  so  abruptly,  that  the  breadth  of  the  cri- 
coid cartilage  behind  becomes  three  times  as  great  as  it  is  in 


THE  LARYNX.  125 

front,  under  the  inferior  margin,  of  the  thyroid  cartilage.  The 
superior  margin  has  on  each  side,  behind,  a  little  head,  or  con- 
vexity, which  receives  the  base  of  the  corresponding  arytenoid 
cartilage,  and  forms  with  it  a  ball  and  socket  joint. 

The  interior  surface  of  the  cricoid  cartilage  is  smooth,  and 
covered  By  the  lining  membrane  of  the  larynx.  Its  exterior 
surface  is  flattened  on  each  side  behind,  by  the  posterior  crico- 
arytenoid  muscles;  it  is  marked  also  laterally  by  other  muscles, 
and  by  the  inferior  cornu  of  the  thyroid  cartilage. 

.The  cricoid  cartilage  is  embraced  by  the  inferior  margin  of 
the  thyroid,  but  in  such  a  way  that  a  triangular  interval  is  left 
in  front  between  the  two  cartilages. 

This  interval  is  filled  by  a  ligament  adhering  to  its  margins 
called  the  middle  Crico-Thyroid,  to  distinguish  it  from  the  li- 
gamentous  junction  between  the  inferior  cornua  of  the  thyroid, 
and  the  sides  of  the  cricoid.  The  middle  ligament  has  some 
small  apertures  in  it  for  the  passage  of  blood  vessels  and  of 
nerves.  It  is  the  part  commonly  cut  in  the  operation  of  laryn- 
gotomy. 

The  Arytenoid  Cartilages  (Cartilagines  JJrytanoidecK]  re- 
semble triangular  pyramids  curved  backwards,  and  about  six 
lines  long.  They  are  placed  on  the  upper  margin  of  the  cri- 
coid cartilage  behind.  The  anterior  face  of  each  is  uneven,  and 
divided  into  two  concavities;  the  posterior  face  forms  a  single 
cylindrical  concavity;  and  the  internal  face,  by  which  it  approx- 
imates its  fellow,  is  nearly  flat.  When  joined  together,  the 
two  cartilages  resemble  the  mouth  or  spout  of  a  pitcher,  from 
whence  their  name.  Their  bases  are  hollowed  into  a  small  gle- 
noid  cavity,  for  articulating  with  the  cricoid  cartilage. 

A  synovial  capsule  is  reflected  over  the  articulation,  between 
the  arytenoid  and  the  cricoid  cartilage:  this  capsule  is  strength- 
ened by  a  few  scattered  ligamentous  fibres. 

The  Epiglottis  Cartilage  (Epiglottis]  is  situated  on  the  pos- 
terior face  of  the  base  of  the  os  hyoides,  being  enclosed  partial- 
ly by  the  two  sides  of  the  thyroid  cartilage.     Its  general  form 
is  that  of  an  oval  disk;  the  upper  margin  of  it  is  thin  and  round- 
VOL.  II.— IT 


126  ORGANS  OF  RESPIRATION. 

ed,  and  the  lower  part  is  elongated  into  a  pedicle  which  adheres 
to  the  entering  angle  of  the  thyroid  cartilage. 

Its  surfaces,  though  nearly  flat,  are  not  fully  so;  for,  anterior- 
ly, it  forms  a  cylindrical  convexity,  and  posteriorly,  a  cylindri- 
cal concavity,  from  side  to  side.  When  nicely  stripped  of  its 
covering,  a  number  of  very  small  foramina  are  seen  to  exist  in 
it,  which  give  passage  principally  to  the  ducts  of  muciparous 
glands.  Its  connexions,  aided  by  its  natural  elasticity,  keep  it 
in  a  vertical  attitude  behind  the  base  of  the  tongue;  its  round- 
ed margin  is  elevated  above  the  latter,  and  overlooks  it. 

„ 

In  addition  to  the  preceding  cartilages,  there  are  always  two, 
and  sometimes  four  others.  On  the  top  of  each  arytenoid  is  to 
be  found  one,  (Corniculum  Laryngis:)  it  is  somewhat  trian- 
gular and  elongated;  its  inferior  face  is  attached  by  a  few  liga- 
mentous  fibres  to  the  end  of  the  arytenoid;  it  is  included  in  the 
soft  parts,  and  is  very  moveable.  The  others,  when  they  exist, 
are  found  on  the  margin  of  the  glottis,  in  the  duplicature  of  the 
membrane  which  is  extended  from  the  side  of  the  epiglottis  to 
the  tip  of  the  arytenoid  cartilage. 

From  the  whole  superior  margin  of  the  thyroid  cartilage  in- 
cluded between  its  greater  cornua,  there  proceeds  upwards  a 
thin  lamina  of  somewhat  condensed  cellular  substance,  which  is 
attached  to  the  inner  margin  of  the  base  and. of  the  cornua  of 
the  os  hyoides  their  whole  length.  It  fills  completely  the  space 
between  the  os  hyoides  and  the  thyroid  cartilage.  This  mem- 
brane is  called  the  middle  Thyreo-hyoid  Ligament,  (Ligament. 
Thyreo-Hyoid.  Medium,)  though  its  ligamentous  character  is 
by  no  means  well  developed.  It  completes  the  periphery  of 
the  larynx  in  the  space  alluded  to,  and,  from  its  thin  yielding 
nature,  presents  no  obstacle  to  the  motions  of  the  os  hyoides 
and  of  the  thyroid  cartilage  upon  each  other. 

The  posterior  margin  of  this  membrane,  on  each  side,  is 
bounded  by  a  long,  rounded,  fibrous  chord,  the  Lateral  Thyreo- 
Hyoid  Ligament,  (Ligamenlum  Thyreo-Hyoideum  Laterale.) 
The  latter  is  extended  from  the  cornu  major  of  the  thyroid  car- 
tilage to  the  tuberculated  extremity  of  the  os  hyoides,  and. fre- 
quently contains,  about  its  centre,  a  small,  oval  cartilage  or 


THE  LARYNX.  127 

bone,    (Cartilago-Triticea,)  not  quite  so  large  as  a  grain  of 
wheat. 

Immediately  under  the  body  of  the  os  hyoides,  between  its 
concave  face  and  the  middle  thyreo-hyoid  ligament,  is  a  small 
sac  or  cell  formed  between  the  laminae  of  the  ligament,  and  fre- 
quently extending  itself  downwards  as  far  as  the  notch  of  the 
thyroid  cartilage;  it  is  flat  about  four  or  five  lines  in  its  trans- 
verse diameter,  and  presents  a  shining  surface.  I  have  never 
seen  a  fluid  in  it  in  the  natural  state;  its  secretion,  however, 
sometimes  becomes  excessive,  and  it  is  then  elongated  down- 
wards over  the  front  of  the  thyroid  and  of  the  cricoid  cartilage, 
as  far  as  the  isthmus  of  the  thyroid  gland.  In  this  state  it  fre- 
quently forms  a  small  fistulous  opening,  at  its  lower  end,  through 
the  skin,  which  is  marked  by  a  fold  of  the  latter  across  the 
neck.  The  true  pathology  of  the  disease  was  first  pointed  out 
by  Dr.  Physick,  who  cures  it,  in  some  cases,  by  the  introduc- 
tion of  lunar  caustic,  and  in  others  by  extirpation. 

The  Thyreo-Arytenoid  Ligaments  are  two  in  number,  on 
each  side  of  the  larynx;  one  above  the  other,  at  the  distance  of 
three  lines.  The  inferior  is  extended  from  the  anterior  angle 
of  the  base  of  the  arytenoid  cartilage  to  the  inferior  part  of  the 
entering  angle  of  the  thyroid,  and,  by  converging  towards  its 
fellow,  is  inserted  there  in  contact  with  it.  Its  fibrous  structure 
is  very  distinct.  It  also  bears  the  name  of  Ligamentum  Vo- 
cale,  from  its  bordering  the  rima  glottidis.  The  superior  thy- 
reo-arytenoid  ligament  arises  from  the  middle  of  the  anterior 
edge  of  the  arytenoid  cartilage,  and  is  also  inserted  into  the  en- 
tering angle  of  the  thyroid;  it  is  more  distant  from  its  fellow 
than  the  lower  one,  and  goes  almost  parallel  with  it;  so  that  the 
opening  between  the  two  is  both  larger  and  more  like  an  ob- 
long. Its  fibrous  structure  is  less  distinct  than  that  of  the  lower. 
Both  the  upper  and  the  lower  ligaments  are  covered  by  a  re- 
flection of  the  lining  membrane  of  the  larynx,  and  are  small, 
round  fibrous  threads,  which  are  rendered  more  or  less  tense  by 
the  action  of  the  small  muscles  of  the  larynx. 

The  superior  thyreo-arytenoid  ligament  is  attached,  in  its 
whole  length,  by  a  triangular  fibro-muscular  layer  to  the  pedi- 
cle of  the  epiglottis:  the  posterior  margin  of  this  layer  is  dis- 


128  ORGANS  OF  RESPIRATIOJf. 

tinctly  muscular,  and  must  have  the  effect  of  drawing  the  liga- 
ment upwards. 

There  are  several  pairs  of  muscles  belonging  to  the  larynx. 

1.  The  Thyreo-Hyoideus,  as  observed  in  the  former  account 
of  this  muscle,  looks  like  a  continuation  of  the  sterno-thyroideus. 
It  arises,  obliquely,  from  the  side  of  the  thyroid  cartilage  by  the 
ridge,  there;  and  running  upwards,  it  is  inserted  into  a  part  of 
the  base,  and  into  nearly  all  the  cornu  of  the  os  hyoides. 

When  the  thyroid  cartilage  is  fixed,  it  draws  down  the  os 
hyoides;  but  when  the  latter  is  fixed,  it  draws  up  the  thyroid 
cartilage. 

2.  The  Crico-Thyroideus  arises,  tendinous  and  fleshy,  from  the 
the  anterior  lateral  surface  of  the  cricoid  cartilage,  and  passes 
upwards  and  backwards,  to  be  inserted  into  the  inferior  cornu 
of  the  thyroid  cartilage,  and  the  adjacent  part  of  its  inferior 
edge. 

Use,  to  draw  these  cartilages  obliquely  together. 

3.  The  Crico-Arytenoideus  Posticus  arises  from  the  back  of 
the  cricoid  cartilage,  occupying  its  excavation,  and  is  inserted 
into  the  posterior  part  of  the  base  of  the  arytenoid  cartilage. 

It  draws  the  arytenoid  backwards,  and  makes  the  ligaments 
tense. 

4.  The  Crico-Arytenoideus  Lateralis  arises  from  the  side  of 
the  cricoid  cartilage,  and  is  inserted  into  the  side  of  the  base  of 
the  arytenoid. 

Use,  to  draw  the  latter  outwards,  and  open  the  chink  of  the 
glottis. 

5.  The  Thyreo-Arytenoideus  arises  from  the  posterior  face 
of  the  thyroid  cartilage,  near  its  angle,  and  the  middle  crico- 
thyroid  ligament,  and  is  inserted  into  the  anterior  edge  of  the 
arytenoid  cartilage. 

Use,  to  relax  the  ligaments  of  the  glottis. 


THE  LARYNX.  129 

6.  The  Arytenoideus  Obliquus  arises  from  the  base  of  one 
arytenoid  cartilage,  and  is  inserted  into  the  tip  of  the  other. 
It  is  a  very  small  fasciculus,  and  sometimes  only  one  muscle 
exists. 

Use,  to  close  the  chink  of  the  glottis. 

7.  The  Arytenoideus  Transversus  is  always  a  single  muscle, 
which  arises  posteriorly  from  the  whole  length  of  one  arytenoid 
cartilage,  excepting  a  little  part  of  the  tip,  and  is  inserted,  in  a 
corresponding  manner,  into  the  other.     It  fills  up  the  cylindri- 
cal concavity  of  the  arytenoid  cartilages. 

Use,  to  close  the  chink  of  the  glottis. 

8.  The  Thyreo-Epiglottideus  consists  in  a  few  fibres,  and 
arises  from  the  posterior  face  of  the  thyroid  cartilage  near  its 
entering  angle.     It  is  inserted  into  the  side  of  the  epiglottis. 

Use,  to  draw  the  epiglottis  downwards. 

9.  The  Aryteno-Epiglottideus  consists  also  in  a  few  indis- 
tinct fibres,  and  arises  from  the  superior  lateral  parts  of  the  ary- 
tenoid cartilage.     It  is  inserted  into  the  side  of  the  epiglottis. 

Use,  to  draw  the  epiglottis  downwards. 

These  two  last  muscles  are  generally  so  small  and  undefined, 
that  they  cannot  be  satisfactorily  distinguished  from  the  adja- 
cent soft  parts. 

On  the  posterior  face  of  the  thyroid  cartilage,  of  the  middle 
thyreo-hyoid  ligament;  and  on  each  side  of  the  epiglottis  carti- 
lage, surrounding  its  lower  part  with  the  exception  of  its  poste- 
rior face,  there  is  an  accumulation  of  cellular  and  adipose  sub- 
stance. In  the  lower  part  of  this  substance  there  are  several 
small  glandular  bodies,  sometimes  insulated  and  sometimes  col- 
lected together,  which  detach  their  prolongations  into  the  fora- 
mina of  the  epiglottis  cartilage,  and  seem  to  open  thereby  on 
its  laryngeal  surface:  they  are  mucous  glands. 

The  Arytenoid  Gland,  which  is  also  muciparous,  is  situated 
in  front  of  the  arytenoid  cartilage,  in  the  duplicature  of  the  mu- 


130  ORGANS  OP  RESPIRATION. 

cous  membrane  which  passes  from  the  side  of  the  epiglottis  car- 
tilage to  the  arytenoid.  It  is  a  small  body  of  a  grayish  colour, 
resembling  the  letter  L,  and  consists  in  distinct  grains;  it  is 
supposed  to  have  its  excretory  ducts  opening  into  the  larynx. 
It  is  frequently  wanting. 

The  Interior  Face  of  the  Larynx  is  lined  by  a  mucous  mem- 
brane, continuous  above  with  that  of  the  mouth  and  pharynx, 
and  below  with  that  of  the  trachea.  Where  it  is  reflected  from 
the  base  of  the  tongue  to  the  epiglottis  cartilage,  it  forms,  as 
described,  a  well  marked  vertical  fold  or  fraenum  in  front  of 
the  middle  of  the  latter,  and  on  each  side  of  this  middle  fold 
there  is  another,  not  so  distinct,  but  varying  in  different  sub- 
jects. Beneath  the  middle  fold  is  the  strong  fibre-muscular 
connexion  with  the  root  of  the  tongue.*  The  three  folds  form 
two  pouches  in  front  of  the  epiglottis,  in  which  food  is  some- 
times lodged.  The  mucous  membrane  also  forms  the  duplica- 
ture  on  each  side  already  alluded  to,  which  passes  from  the  la- 
teral part  of  the  epiglottis  cartilage  to  the  arytenoid  of  the  same 
side  of  the  body.  This  duplicature  forms  the  superior  boundary 
of  the  cavity  of  the  larynx,  and  is  very  soft  and  extensible,  per- 
mitting freely  the  epiglottis  to  be  depressed  and  to  rise  again 
into  its  vertical  position.  The  duplications  of  the  two  sides, 
taken  together,  form  an  oblong  oval  opening  into  the  larynx, 
passing  very  obliquely  upwards  and  forwards  to  the  epiglottis, 
and  terminated  behind  by  a  notch  between  the  cornicula  laryn- 
gis.  At  the  latter  place  the  mucous  membrane  is  wrinkled  and 
loose,  so  as  to  permit,  by  its  extensibility,  free  motion  to  the 
arytenoid  cartilages. 

*  A  muscle  of  a  triangular  shape  has  lately  been  observed  by  the  English  ana- 
tomists,f  situated  in  front  of  the  epiglottis,  passing  to  it  from  the  base  of  the  os 
hyoides:  it  is  called  Hyo-Epiglottideus.  The  observations  on  its  existence  have 
not  yet  been  repeated  sufficiently  often  to  determine  whether  it  belongs  to  the 
normal  structure  of  the  body  or  not;  and  in  my  own  dissections,  for  the  purpose 
of  ascertaining  its  existence,  it  has  not  occurred.  Albinus,  Scemmering,  and 
others,  speak  of  the  occasional  existence  of  muscular  fibres  there.  A  strong  mus- 
cle is  found  there  in  the  lower  animals,  as  stated  in  the  description  of  the  tongue, 
vol.  1st. 

1  Am.  Med.  Jour.  vol.  v.  p.  475. 


THE  LARYNX.  131 

After  adopting  the  preceding  arrangement,  the  lining  mem- 
brane of  the  larynx  passes  downwards;  it  covers  smoothly  the 
posterior  face  of  the  epiglottis,  adhering  closely  to  it;  but,  when 
it  reaches  the  thyreo-arytenoid  ligaments,  it  is  tucked  in  be- 
tween the  upper  and  the  lower  one,  so  as  to  form,  on  either  side, 
an  oblong  pouch,  the  bottom  of  which  is  broader  than  its  ori- 
fice between  the  ligaments.  This  pouch  is  the  ventricle  of 
Galen,  or  of  Morgagni,  or  of  the  larynx;  it  projects  into  the 
fatty  glandular  matter  on  the  posterior  face  of  the  thyroid  car- 
tilage, and  has  its  base  resting  on  the  thyreo-arytenoid  muscle. 
Its  superior  end  reaches  almost  as  high  as  the  upper  margin  of 
the  thyroid  cartilage,  and  it  has  some  small  fasciculi  of  muscular 
fibre  on  its  interior  which  seem  appropriated  to  its  use.  The 
continuation  of  the  membrane  afterwards  lines  smoothly  the 
cricoid  cartilage,  and  abounds  there  in  mucous  follicles. 

That  portion  of  the  larynx  which  is  formed  by  the  thyreo- 
arytenoid  ligaments,  and  the  pouches  between  them,  is  the 
structure  essential  to  the  formation  of  voice.  The  opening  be- 
tween the  two  lower  ligaments  is  the  Rima  Glottidis,  and  the 
space  between  the  upper  ligaments  and  the  duplicature  of  the 
mucous  membrane  passing  from  the  arytenoids  to  the  epiglottis 
cartilage,  may  be  termed  the  Glottis. 

The  Epiglottis  Cartilage  is  principally  useful  in  preventing 
articles  of  food  from  falling  into  the  glottis,  either  in  swallow- 
ing or  in  vomiting.  The  strength  of  its  muscles,  however,  does 
not  seem  to  be  sufficient  to  draw  it  down  over  the  glottis,  as- 
many  physiologists  suppose;  on  the  contrary,  I  am  induced  to- 
believe  that  the  glottis  is  rather*ftrawn  upwards  to  it.  If,  on 
any  occasion,  it  be  depressed  or  bent  down  over  the  glottis,  the 
position  must  be  caused  by  mechanical  pressure  from  the  bulk 
of  the  article  swallowed.  But  the  latter  explanation  is  not  suf- 
ficient to  account  for  the  swallowing  of  fluids,  or  of  a  very  small 
body,  as  a  pill  or  a  crumb  of  bread. 

Impressed  with  these  objections,  and  unsatisfied  with  the 
common  theory,  I  had  an  opportunity,  in  a  dissection  a  few 
years  ago,  of  witnessing  a  position  of  these  parts  which  afforded 
a  satisfactory  explanation.  The  subject  was  a  robust,  muscular 
man,  who  had  died  suddenly.  The  upper  orifice  of  the  glottis 
was  closed  and  protected,  but  by  an  arrangement  precisely  the 


132  ORGANS  OF  RESPIRATION. 

• 

reverse  of  the  received  opinion;  for  the  epiglottis,  retaining  its 
naturally  erect  position,  with  a  slight  inclination  backwards,  had 
the  opening  of  the  glottis  drawn  up  so  as  to  come  in  contact 
with  its  posterior  face.  The  cricoid  cartilage,  as  has  been  men- 
tioned, slopes  on  its  superior  margin  upwards  and  backwards; 
the  front  surfaces  of  the  arytenoid  cartilages,  in  their  natural 
position,  are  nearly  on  a  line  with  this  slope,  or  a  continuation 
of  it;  the  whole  may,  therefore,  be  considered  in  the  light  of 
an  oblique  plane,  rising  up  behind  the  epiglottis  cartilage.  By 
a  very  slight  additional  elevation  of  this  plane  along  with  the 
rotatory  motion  of  the  thyroid  cartilage  upon  its  lesser  cornua, 
the  plane  is  caused  to  come  in  contact  with  the  posterior  face 
of  the  epiglottis,  and  thereby  to  close  the  upper  opening  of  the 
glottis. 

The  principal  agents  in  this  motion  are  the  thyreo-hyoid  mus- 
cles, the  contraction  of  which,  causing  the  larynx  to  ascend,  the 
opening  of  the  glottis  is'brought  up  behind  the  epiglottis,  and' 
thereby  secured  from  the  introduction  of  food  into  it.  Whether 
the  food  be  passed  from  the  mouth  into  the  stomach,  as  in 
swallowing,  or  from  the  stomach  into  the  mouth,  as  in  vomiting, 
is  equally  unimportant;  and  the  security  is  the  same,  whether 
the  article  be  small  or  large,  fluid  or  solid.  Several  years  ago, 
I  dissected  a  gentleman  who  had  symptoms  of  sore  throat  with 
swelling  of  the  neck,  superadded  to  those  of  pulmonary  con- 
sumption: during  the  existence  of  his  sore  throat,  in  addition 
to  the  usual  difficulty  of  swallowing,  he  was  frequently  affected 
in  the  act,  with  strangulation  to  an  alarming  and  distressing  de- 
gree. In  the  dissection,  it  was  found  that  an  abscess,  of  con- 
siderable extent,  existed  between  the  os  hyoides  and  the  thyroid 
cartilage,  ancl  involved  the  thyreo-hyoid  muscles.  Without 
knowing  at  the  time  the  value  of  this  observation,  I  arn'now 
persuaded  that  the  strangulation  arose  from  the  inactivity  of 
the  thyreo-hyoid  muscles.  In  some  ulcerations  of  the  epiglottis 
cartilage,  which  I  have  had  an  opportunity  of  seeing,  the  up- 
per circular  portion,  which  projects  above  the  root  of  the  tongue 
has  been  lost;  if  the  accident  be  confined  to  that  extent  only, 
deglutition  is  not  much  impaired,  because  still  enough  of  the 
epiglottis  is  left  to  perform  the  office  assigned  to  it,  as  the  up- 
per part  is  less  essential.  The  cases  of  its  reputed  loss  by  wounds, 


THE  TRACHEA.  133 

must  be  considered  as  applying  themselves  to  this  upper  portion 
only,  because  a  wound  low  enough  to  remove  the  whole  body, 
would  cause  such  a  destruction  of  the  rima  glottidis,  as  to 
produce  ah  embarrassment  of  respiration,  incompatible  with 
life.  * 

It  is  probable  that  the  inferior  constrictors  of  the  pharynx,  as 
well  as  the  stylo-pharyngeal  muscles,  assist  in  this  use  of  the 
thyreo-hyoidei. 

There  is  a  well  marked  difference  in  the  larynx  of  the  two 
sexes.  In  the  female,  it  is  generally  smaller  by  one-third  than 
it  is  in  the  male;  the  thyroid  cartilage  is  also  less  prominent,  in 
consequence  of  its  two  halves  uniting  at  an  angle  more  obluse, 
the  pomum  Adami  is,  therefore,  seldom  conspicuous.  The  rima 
glottidis  is  also  smaller  in  women. 

The  nerves  of  the  larynx  come  principally  from  the  superior 
and  the  inferior  laryngeal  branches  of  the  par  vagum. 


CHAPTER  II. 

OF  THE  TRACHEA,  AND  THE  GLANDS  BORDERING  UPON  IT. 
SECT.  I. — THE  TRACHEA. 

THE  Trachea,  or  Aspera  Arteria,  is  a  cylindrical  canal  of  four 
or  five  inches  in  length  and  about  nine  lines  in  diameter,  com- 
municating with  the  lungs  for  the  transmission  of  air.  It  opens 
into  the  larynx  above,  by  being  attached  to  the  inferior  mar- 
gin of  the  cricoid  cartilage,  and  terminates  in  the  thorax  oppo- 
site the  third  dorsal  vertebra,  by  two  ramifications  called  Bron- 
chia. In  this  course  it  is  situated  over  the  middle  line  of  the 
neck,  beneath  the  sterno-thyroid  muscles,  and  separated  from 
them  by  the  deep-seated  fascia  of  the  neck  and  the  adipose  mat- 
ter beneath  it.  It  is  placed  in  front  of  the  oesophagus,  between 
the  primitive  carotid  arteries  and  the  internal  jugular  veins. 
When  it  has  got  into  the  thorax,  it  inclines  slightly'to  the  right 
VOL.  II.— 18 


134  ORGANS  OF  RESPIRATION. 

side  as  it  passes  behind  the  curvature  of  the  aorta.  Of  its  two 
branches,  the  right  bronchia  is  larger  than  the  other;  it  is  also 
less  slanting,  and  an  inch  long  before  it  divides;  it  sinks  below 
the  right  pulmonary  artery,  to  penetrate  the  lung  about  the 
fourth  dorsal  vertebra.  The  left  bronchia  being  an  inch  longer, 
sinks  into  the  lung  of  the  left  side,  below  the  corresponding 
pulmonary  artery,  and  opposite  the  fifth  dorsal  vertebra.  The 
bronchise  then  divide  and  subdivide  very  minutely  through  the 
lungs. 

Very  dissimilar  structures  enter  into  the  composition  of  the 
trachea;  they  are  cartilage,  ligamentous  fibre,  muscle  and  a  mu- 
cous membrane. 

The  Cartilage  preserves  the  cylindrical  shape  of  the  trachea, 
and  consists  in  from  sixteen  to  twenty  distinct  rings,  which  are 
deficient  in  the  posterior  third  of  their  circumference.  Each 
ring  is  about  two  lines  broad,  and  half  a  line  thick,  and  is  kept 
apart  from  the  one  above  and  below  it  by  a  small  interstice; 
sometimes,  however,  they  run  into  each  other. 

There  is  an  almost  uniform  similitude  between  these  rings;  the 
principal  departure  from  which  is  observed  in  the  first  being  ra- 
ther broader  in  front  than  the  others,  and  in  the  last  ring,  which, 
by  its  corset-like  shape  in  front,  contributes  to  the  beginning  of 
each  bronchia. 

The  rings  of  the  Bronchia?  are,  like  those  of  the  trachea,  defi- 
cient in  their  posterior  third,  and  the  same  arrangement  holds 
during  their  primitive  ramifications  in  the  lungs.  But  as  they  sub- 
divide more  and  more,  the  cartilages  do  not  succeed  each  other 
so  closely,  and  are  smaller  segments  of  circles,  they  are  not  re- 
gularly deficient  at  the  posterior  third;  but,  in  place  of  the  latter, 
the  whole  periphery  of  the  bronchial  ramification  is  cartilage, 
and  the  latter  consists  in  several  pieces  put  end  to  end.  The 
pieces  become,  after  awhile,  more  and  more  scattered  and  small- 
er, till  they  finally  disappear,  and  the  bronchia  is  simply  mem- 
branous.* At  the  orifice  of  each  branch  of  the  bronchia,  there  is 
a  semiflunar  cartilage,  forming  rather  more  than  one  half  of  its 
circumference,  and  having  its  concave  edge  upwards.  The  whole 
arrangement  resembles  somewhat  the  pasteboard  to  an  eared 
bonnet,  and  is  evidently  to  keep  the  orifice  open. 


THE  TRACHEA.  135 

The  Ligamentous  Structure  of  the  trachea  and  of  the  bron- 
chiae is  very  evident  between  the  proximate  margins  of  the  car- 
tilaginous rings,  and  fills  up  the  intervals  between  them  so  as  to 
make  the  tube  perfect.  This  tissue  may  be  traced  over  the  sur- 
faces of  the  rings,  forming  their  perichondrium,  so  that  they  may 
be  considered  as  embedded  in  it.  It  does  not  exist,  satisfactorily, 
in  the  human  subject,  in  the  interval  behind,  where  a  third  of 
the  ring  is  defective,  its  place  being  supplied  by  a  condensed  cel- 
lular substance;  but  in  the  bullock  it  is  there  also.  In  the  small- 
er ramifications  of  the  bronchiae,  where  a  complete  circle  is 
formed  by  the  juxta-position  of  the  several  little  cartilaginous  seg- 
ments, it  is  probable  that  this  tissue  contributes  to  the  whole  pe- 
riphery of  the  ramification. 

It  possesses  great  elasticity,  which  is  manifested  by  the  rapid 
shortening  of  the  trachea,  when  its  two  extremities  are  stretched 
apart  and  then  suddenly  let  loose.  And  it  is  the  continuance  of 
this  quality  of  elasticity,  in  the  minute  ramifications  of  the  bron- 
chiae, which  proves  the  existence  of  this  tissue  there,  even  when 
it  cannot  be  very  distinctly  seen. 

The  Muscular  Structure  of  the  trachea  exists  at  the  cartilagi- 
nous deficiency  in  its  posterior  third,  and  consists  in  a  thin  mus- 
cular plane  whose  fibres  pass  transversely  between  the  interrupt- 
ed extremities  of  the  cartilaginous  rings  of  the  trachea  and  of  the 
bronchiae.  These  transverse  fibres  begin  at  the  first  ring,  and 
exist  all  the  way  down  to  the  lungs :  they  rise  from  the  internal 
faces  of  the  rings,  and  the  intermediate  elastic  ligamentous  tis- 
sue ;  about  a  line  beyond  their  extremities.  Anteriorly,  they  are 
covered  by  the  lining  membrane  of  the  trachea,  and  posteriorly, 
by  the  cellular  tissue  just  spoken  of. 

In  the  lungs,  where  the  cartilages  become  scattered  and  irre- 
gular, the  muscular  fibres  are  said,  by  J.  F.  Meckel,  and  by  M. 
Reisseissen,*  to  perform  the  whole  circuit  of  the  bronchial  rami- 

*  De  Fabrica  Pulmonis.  Berlin,  1822.  M.  Laennec  says  (Traite,  de  1' Ausculta- 
tion, Paris,  1826,  vol.  ii.  p.  189,)  that  he  has  sought  in  vain  to  verify  these  obser- 
vations of  Reisseissen,  but  that  the  manifest  existence  of  circular  fibres  upon 
branches  of  a  middling'  size  and  the  phenomena  of  many  kinds  of  asthma,  induce 
him  to  view,  as  a  thing  well  established,  the  temporary  occlusion  of  the  small 
bronchial  ramifications,  by  a  spasmodic  contraction  of  their  parietes. 


136  ORGANS  OF  RESPIRATION. 

fication,  and  to  be  visible  even  beyond  the  existence  of  tbe  carti- 
laginous pieces.  Soemmering  expresses  a  doubt  of  this  arrange- 
ment.* It  is  very  difficult  in  such  minute  structure  to  arrive  at 
a  satisfactory  conclusion ;  careful  observations,  latterly  made, 
have,  however,  induced  me  to  adopt  the  same  conviction  as  Reis- 
seissen.  Longitudinal  fibres  are  also  said  by  Portal  to  exist  be- 
tween the  contiguous  margins'of  the  cartilaginous  rings,  but  the 
fact  is  far  from  being  ascertained.t 

The  use  of  this  muscular  tissue  has  been  pointed  out,  by  Dr. 
Phyc-ick,  as  follows : — "  In  expectoration,  it  diminishes  the  caliber 
of  the  air  tubes,  so  that  the  air  having  to  pass  out  with  increased 
rapidity  through  them,  its  momentum  will  bring  up  the  inspissated 
fluid  which  may  be  in  its  way."  This  very  ingenious  theory  has 
subsequently  been  advanced  by  M.  Cruveilheir,  of  Paris,  possibly 
without  a  knowledge  of  his  having  been  anticipated ;  but  cer- 
tainly not  without  the  claims  of  the  eminent  individual  to  whom 
we  owe  it,  having  been  established  by  its  publication.! 

The  Mucous  Membrane  of  the  trachea  lines  its  whole  interior 
periphery,  from  the  larynx  to  the  bronchiae,  and  is  continued,  un- 
der the  same  circumstances,  through  the  latter  to  their  minute 
divisions.  It  adheres  very  closely  to  the  contiguous  structure,  and 
is  continued,  in  the  substance  of  the  lungs,  beyond  the  traces  of 
any  of  the  other  tissues  which  compose  the  trachea ;  it  indeed 
terminates  in  the  air  cells.  It  is  very  vascular,  like  other  mu- 
cous membranes;  and  also,  like  them,  the  venous  appears  to  pre- 
vail over  the  arterial  vascularity.  A  successful  minute  injection 
makes  it  look  as  if  it  consisted  of  a  tissue  of  blood  vessels;  thin 
and  red,  it  presents  an  abundance  of  slightly  elevated  longitudi- 
nal folds:  one  of  the  latter,  conspicuous  for  its  greater  size,  ex- 
ists at  the  commencement  of  the  left  bronchia,  and  is  yet  more 
developed  in  the  still-born  infant. 

The  exterior  circumference  of  the  mucous  membrane  is  stud- 

•  Extimje  autem  vel  pcsticz  ejus  fibrze  per  longittidinem,  a  cartilagine  cricoi- 
dea  ad  pulmones  usque  descendant  uc,  vel  in  ipsis  trachea  ramis  haud  parura 
conspicui  sunt. — De  Corp.  Hum.  Fabrica. 

f  Anat.  Med. 

t  Wistar's  Anatomy,  3d  edition,  vol.  ii.  p.  64.     Phil.  1821. 


THE  THYROID  GLAND.  137 

ded  with  muciparous  glands,  about  the  size  of  millet  seed.  These 
glands  are  particularly  conspicuous  and  abundant  on  the  poste- 
rior part  of  the  trachea  and  of  the  bronchiae,  where  the  deficien- 
cy of  the  cartilaginous  rings  is  supplied  by  the  membranous  struc- 
ture only ;  and  more  of  them  exist  at  the  lower  part  of  the  tra- 
chea and  upon  the  roots  of  the  bronchia?  than  elsewhere.  They 
are  placed  behind  the  muscular  layer,  which  their  excretory 
ducts  have  to  penetrate.  Besides  occupying  these  situations,  they 
are  found  in  the  interstices  between  the  cartilaginous  rings,  but 
here  they  are  much  smaller.  The  mucous  membrane  abounds 
so  much  in  the  orifices  made  by  their  excretory  ducts,  that  it 
looks  cribriform,  which  appearance  is  increased  by  floating  it  in 
water. 

About  the  origins  of  the  bronchiae,  there  is  a  considerable  num- 
ber of  black  coloured  lymphatic  glands,  called  Bronchial,  which 
it  is  easy  to  distinguish  from  the  preceding  by  their  colour  and 
much  greater  size. 

There  are  two  more  glands  of  a  different  character,  which, 
though  they  do  not  enter  into  the  composition  of  the  trachea,  yet, 
from  their  locality,  are  most  conveniently  studied  at  this  time : 
they  are  the  Thyroid  and  the  Thymus. 

SECT.  II. — OF  THE  THYROID  GLAND. 

• 

The  Thyroid  Gland  (Glandula  Thyroided)  is  placed  on  the 
first  and  second  rings  of  the  trachea,  and  on  the  sides  of  the 
larynx. 

It  consists  in  a  middle  portion,  which  is  thin,  of  variable  mag- 
nitude in  different  individuals,  sometimes  entirely  wanting,  and 
which,  being  stretched  across  the  upper  part  of  the  trachea  just 
below  the  larynx,  is  called  its  isthmus;  and  of  two  lobes,  one  on 
each  side,  which,  being  flattened  and  ovoidal,  are  extended  up- 
wards on  the  side  of  the  larynx,  and  downwards  on  the  side  of 
the  trachea  and  of  the  oesophagus.  Frequently  from  the  superior 
part  of  the  isthmus,  and  most  commonly  on  its  left  side,  a  small 
pyramidal  process  runs  upwards  in  front  of  the  cricoid  and  of 
the  thyroid  cartilage,  and  is  attached,  by  ligamentous  fibres  to 


138  ORGANS  OF  RESPIRATION. 

the  os  hyoides ;  this  process,  however,  varies  much  in  size  and 
length  :  I  have  never  seen  it  double.  According  to  Morgagni 
and  Meckel,  its  existence  is  much  more  common  than  its  ab- 
sence, which  corresponds  with  my  own  observations.  The  thy- 
roid gland,  when  extended,  measures  about  three  inches  from 
side  to  side. 

It  is  covered  in  front  by  the  sterno-hyoid  and  thyroid  muscles, 
and  laterally  by  the  omo-hyoid  and  the  sterno-mastoid.  Em- 
bracing the  trachea  and  the  sides  of  the  larynx,  its  lobes  repose 
upon  the  primitive  carotids,  and  the  internal  jugular  veins. 

The  thyroid  gland  has  a  capsule  which  is  not  very  easily  raised 
up,  but  serves  to  give  it  a  polish ;  it  is  also  invested  by  the  con- 
densed cellular  membrane  of  the  part  called  fascia  profunda 
colli.  Its  surface  is  smooth  and  uniform.  It  is  of  a  dark  brown 
colour.  When  cut  into  or  torn,  it  is  seen  to  consist  of  several 
lobules  adhering  to  each  "other:  but  this  arrangement  is  not  very 
distinct,  except  in  an  enlarged  or  diseased  state ;  and  may  be 
traced  most  easily  by  following  the  course  of  the  large  blood  ves- 
sels, which  pass  in  the  interstices  between  the  lobules.  The  lat- 
ter contain  many  small  vesicles,  or  cells,  filled  with  a  transparent 
or  yellowish  and  somewhat  unctuous  fluid ;  the  cells  are  fre- 
quently in  a  collapsed  state,  which  prevents  them  from  being  ma- 
nifest to  the  naked  eye. 

There  are  four  considerable  arteries  which  supply  this  body, 
two  on  each  side,  one  coming  from  the  external,  carotid  and  the 
other  from  the  subclavian.  The  veins  follow  the  course  of  the 
arteries  for  the  most  part.  Bichat  has  made  a  very  interesting 
remark  on  the  subject  of  its  blood  vessels ;  that,  notwithstanding 
their  size  and  number,  and  minute  ramifications  in  it,  much  less 
blood  remains  in  its  capillary  system  than  in  that  of  the  liver  or 
kidney,  as  is  proved  by  the  quantity  of  water  it  tinges  in  mace- 
ration; he,  therefore,  infers  that  the  capillary  system  is  less  abun- 
dant. 

Anatomists  have  sought  in  vain  for  one  or  more  excretory 
ducts  to  this  body,  and  some  have  imagined  that  they  had  found 
them  terminating  in  the  trachea,  or  in  the  larynx.  Santorini  con- 
sidered the  pyramidal  process,  from  the  isthmus  as  the  desired 
duct.  The  emphysema  with  which  the  gland  has  sometimes 
been  affected,  was  supposed  to  be  a  proof  of  its  communicating 


THE  THYMUS  GLAND.  139 

with  the  trachea  by  excretory  tubes ;  but  it  is  more  probable  that 
the  air  was  forced  into  the  cellular  substance,  uniting  its  lobules, 
and  not  into  the  structure  itself  of  the  gland.  The  settled  opi- 
nion now  seems  to  be,  that  whatever  fluid  it  secretes  is  conveyed 
away  by  the  lymphatic  vessels.  Meckel  has  suggested,  that  as 
this  gland  is  more  voluminous  proportionately  in  early  infancy, 
particularly  its  pyramidal  process,  possibly  the  duct  may  be  ob- 
literated when  the  gland  begins  to  be  restrained  in  its  growth ; 
but  if  this  were  the  case,  the  duct  ought  to  have  been  found 
during  the  period  indicated.  The  probability  is,  that  it  is  a  di- 
verticulum  of  blood  from  the  salivary  glands  during  the  inter- 
in  ittence  of  their  action ;  and  from  the  marked  sympathy  between 
it  and  the  brain  in  goitre,  it  may  exercise  a  corresponding  func- 
tion on  this  organ  during  its  intervals  of  repose. 

Duverney*  has  described  a  small  azygous  muscle  on  the  mid- 
dle line  of  the  body,  coming  from  the  under  margin  of  the  base 
of  the  os  hyoides,  and  running  over  the  middle  of  the  thyroid 
cartilage,  to  be  inserted  into  the  upper  margin  of  the  isthmus  of 
the  thyroid  gland.  Soemmering  calls  it  Levator  Glandulae  Thy- 
roideae,  and  speaks  of  it  as  being  found  more  frequently  on  the 
left  side,  and  about  half  of  the  breadth  of  the  thyreo-hyoideus. 
After  many  special  examinations  for  it  I  have  found  it  in  but  few 
instances ;  I,  therefore,  consider  it  rare ;  though  without  a  close 
attention  to  structure,  the  pyramidal  process  of  the  isthmus  of 
the  gland  may,  from  the  similitude  of  colour  and  position,  be 
very  readily  mistaken  for  it,  which  I  have  reason  to  believe  is 
frequently  the  case.f  Some  few  fibres  are  often  found  going  to 
the  isthmus  of  the  gland  from  the  crico-thyroid,  and  the  thyreo- 
hyoid  muscles,  or  from  the  thyroid  cartilage. 


SECT.  III. OF  THE  THYMUS  GLAND. 

This  body  (Glans  Thymus)  is  placed  between  the  trachea  and 

*   Essai  D'Anatomie  en  tableux  imprimes,  pi.  IV.   Paris,  1745. 

f  The  unassisted  eye,  in  a  strong  light,  is  generally  sufficient  to  determine  the 
structure;  but  in  case  of  doubt,  by  boiling  the  gland,  if  there  be  muscular  fibres 
along  this  process,  their  longitudinal  and  parallel  direction  will  become  evident: 
they  also  may  then  be  torn  asunder,  so  as  to  be  made  still  more  distinct;  whereas, 
the  vesicular  structure  of  the  gland  is  not  susceptible  of  division  into  fibres, 


140  ORGANS  OF  RESPIRATION. 

the  upper  extremity  of  the  sternum.  It  is  irregularly  triangular, 
its  broadest  part  being  above,  and  the  narrower  below.  In  the 
adult,  it  is  in  a  collapsed  and  shrivelled  state,  and  scarcely  pre- 
sents a  vestige  of  what  it  once  was ;  it  is,  therefore,  only  in  the 
infant  that  it  can  be  satisfactorily  studied. 

At  birth,  it  is  much  larger,  not  relatively,  but  actually,  than  it 
is  in  the  adult,  and  extends  from  the  body  of  the  heart  up  to  the 
thyroid  gland.  It  is  of  a  very  soft  consistence  and  of  a  pink  co- 
lour. It  is  surrounded  by  a  capsule  of  cellular  substance,  which, 
when  removed,  permits  the  gland  to  be  resolved  into  two  lobes, 
one  on  either  side,  which  adhere  to  each  other.  These  lobes 
may  be  separated  with  facility  into  lobules,  and  contain  a  whitish 
fluid. 

A  good  Essay  on  the  structure  of  this  gland,  has  latterly  been 
published  by  the  distinguished  British  surgeon  and  anatomist,  Sir 
Astley  Cooper,*  illustrated  by  excellent  plates.  From  this  it  ap- 
pears that  the  lobules  of  the  gland  are  formed  of  vesicles  of  va- 
rious sizes,  all  discharging  into  a  duct  which  runs  from  one  end 
of  the  gland  to  the  other,  the  consistence  of  which  duct  is  ex- 
tremely feeble.  .This  duct  and  the  vesicles  may  be  filled  with 
an  injection,  by  means  of  a  pipe  introduced  into  the  substance  of 
the  gland.  A  large  lymphatic  trunk  passes  from  the  gland,  on 
each  side,  into  the  transverse  vein. 

Sir  Astley  thinks,  or,  rather,  asks,  whether  this  gland  does  not 
prepare  a  fluid  for  foetal  nourishment,  in  the  absence  of  proper 
chylification,  during  foetal  life?  inasmuch  as  all  the  elements  of 
the  blood  are  upon  chemical  analysis,  found  in  the  fluid  contained 
in  its  cavities. 

It  is  visible  in  the  third  month  of  gestation,  and  continues  to 
grow  till  the  end  of  the  second  year  of  extra-uterine  life.  It  then 
collapses,  and  its  structure  is  effaced  about  the  twelfth  year;  its 
remains  are  scarcely  distinguishable  subsequently  from  the  sur- 
rounding cellular  substance.  No  excretory  duct  has  been  found 
for  it,  unless  we  .may  consider  as  such  the  lymphatic  trunk  al- 
luded to  by  Sir  Astley  Cooper,  and,  though  it  clearly  belongs  to 
foetal  and  infantile  existence,  its  use  is  problematical.  The  pro- 
bability is,  that  it  is  a  diverticulum  of  blood  from  the  lungs 

*  London,  1832. 


THE  LUNGS.  141 


during  their  state  of  quiescence  in  foetal  life,  and  until  their  struo 
ture  becomes  confirmed  and  proportionately  evolved*. 


CHAPTER  III. 


OF  THE  LUNGS. 

The  Lungs  (Pulmones)  are  the  essential  seat  of  the  process 
of  respiration,  and  occupy  the  greater  part  of  the  cavity  of  the 
thorax,  as  formed  by  the-  ribs  and  the  intercostal  muscles  on 
the  sides,  by  the  sternum  and  its  cartilages  in  front,  by  the 
dorsal  vertebrae  behind,  and  by  the  diaphragm  below.  They 
are  two  bodies,  placed  one  on  either  side  of  the  thorax,  and  se- 
parated from  each  other  by  the  heart  and  its  great  vessels.  As 
the  heart  is  the  only  organ  of  much  volume  which  is  also  in- 
cluded in  the  cavity  of  the-  thorax,  the  size  of  the  lungs  is  in  a 
direct  relation  with  the  capacity  of  the  latter;,  and  may,  therefore, 
be  known  by  external  indications  in  the  living  body.  It  is 
probable  that  there  is  no  void)  or  only  a  very  small  one,  be- 
tween the  sides  of  the  lungs  and  the  sides  of  the  thorax. 

Each  lung  forms  an  irregular  cone,  the  apex  of  which  is  above, 
and  the  base  below;  the  latter,  from  resting  upon  the  diaphragm, 
is,  consequently,  oblique  from  before  backwards  and  downwards, 
and  is  also  concave.  The  surface  which  reposes  against  the  pe- 
riphery of  the  side  of  the  thorax,  is  uniformly  rounded,  but  that 
which  looks  towards  its  fellow,  is  concave,  from  being  pressed 
in  by  the  heart.  From  the  oblique  direction  of  the  diaphragm, 
the  vertical  diameter  of  the  lung  behind,  when  it  is  fully  dis- 
tended, goes  from  the  first  to  the  last  rib,  and  is,  consequently, 
much  more  considerable  than  the  vertical  diameter  in  front, 
which  extends  only  from  the  first  rib  to  the  inferior  end  of  the 
second  bone  of  the  sternum,  or,  in  other  words,  to  a  level  with 
the  tendinous  centre  of  the  diaphragm. 

The  left  lung  is  divided  into  two  lobes  by  a  deep  fissure, 
VOL.  II.— 19' 


142  ORGANS  OP  RESPIRATION. 

which  begins  behind,  on  a  level  with  the  fourth  dorsal  vertebra, 
and  runs  obliquely  downwards  and  forwards  to  the  anterior 
margin  of  its  base.  A  deep  fissure  in  a  nearly  similar  situation 
is  observed  on  the  right  lung;  but  from  it  another  fissure  branches 
out  forwards,  by  which  the  right  lung  is  divided  into  three  lobes. 
The  internal  face  of  the  left  lung  is  also  rather  more  concave 
than  that  of  the  right,  from  the  side  of  the  heart  projecting  into 
it.  The  right  lung  is  more  voluminous  than  the  left,  which 
corresponds  with  the  greater  size  of  the  bronchia  on  this  side, 
but  its  vertical  diameter  is  not  so  great,  from  the  pressure  of 
the  liver  from  below. 

Near  the  middle  of  the  internal  face  of  each  lung  are  to  be 
seen  the  points  of  connexion  with  the  bronchia,  and  with  the 
pulmonary  vessels.  Before  these  the  anterior  margin  is  thin, 
and  more  or  less  winding  where  the  lung  is  introduced  between 
the  heart  and  the  front  parietes  of  the  thorax.  When  the  lungs 
are  fully  inflated,  only  a  very  small  portion  of  the  pericardium 
can  be  seen  here  between  them.  The  posterior  margin  is  thick, 
and  rounded  where  it  rests  against  the  vertebral  column. 

The  whole  rounded  circumference  of  the  lung  as  well  as  its 
base,  though  they  are  in  contact  with  the  parietes  of  the  thorax, 
do  not  adhere  at  any  point  to  them.  The  connexion  of  the 
lung,  constituting  its  root,  as  it  is  called,  and  by  which  it  is 
maintained  in  its  situation,  is  entirely  on  the  side  of  its  concave 
face,  where  the  pulmonary  vessels  and  bronchia  enter,  and 
though  other  attachments  are  frequently  found  springing  from 
different  points  of  the  thorax,  they  are  purely  the  results  of 
disease. 

Of  the.  Texture  of  the  Lungs. 

Each  lobe  of  the  lungs  is  divided  into  a  great  many  distinct 
lobules,  which  adhere  together  by  intermediate  cellular  tissue. 
The  marks  of  these  divisions  are  apparent  on  the  surface  by 
lines  running  in  different  directions,  but  they  are  made  still 
more  distinct  by  tearing  them  asunder.  The  Lobules  are  sub- 
divided into  very  fine  air  vesicles  or  cells,  which  may  be  con- 
sidered as  the  terminations  of  the  ultimate  branches  of  the 
bronchia.  The  opinion  is  generally  held,  that  the  cells  do  not 


THE  LUNGS.  143 

communicate  laterally  with  one  another,  as  the  cells  of  the  bones, 
but  only  with  the  ramifications  of  the  bronchia,  to  which  they 
respectively  belong.  Recent  preparations,  however,  have  in- 
duced me  to  abandon  this  idea,  and  to  conclude  that  the  cells 
of  the  lobules  individually  communicate,  but  not  those  of  dif- 
ferent lobules.  I  have  succeeded  in  proving  this  by  distending 
the  air  cells  with  tallow,  and,  after  the  lung  was  dried,  by  re- 
moving the  tallow  with  spirits  of  turpentine.  This  process 
shows  the  cells  of  their  natural  size,  and  communicating  freely. 

In  tracing  the  terminations  of  the  bronchise,  in  the  substance 
of  the  lungs,  the  parietes  of  these  canals  are  observed  to  become 
very  thin,  and  especially  after  the  cartilaginous  structure  has 
ceased.  The  ramifications  seem  then  to  be  composed  almost 
entirely  of  muscular  fibres,  and  a  lining  of  mucous  membrane: 
the  latter  is  smooth,  polished,  and  so  thin  that  it  is  a  mere  film, 
about  the  thickness  and  transparency  of  the  peritoneum,  where 
it  covers  a  small  intestine.  Longitudinal  folds  may  still  be 
traced  in  the  length  of  the  mucous  membrane,  and,  with  the  aid 
of  a  lens,  mucous  follicles  are  very  perceptible,  in  innumerable 
quantities  all  over  it.  It  may  also  be  remarked,  that  the  bronchiae 
do  not  end  by  a  regular  succession  of  proportionately  finer  and 
finer  branches;  but  that  a  bronchial  trunk,  of  some  lines  in 
diameter,  sends  off  in  different  directions  to  the  contiguous  lo- 
bules, branches  about  the  size  of  a  bristle,  which  are  followed 
with  much  difficulty,  owing  to  their  collapsing;  the  probability 
is,  however,  that  each  one  of  these  branches  belongs  to  a  lobule, 
and  discharges  into  its  cells,  in  a  manner  resembling  a  blow- 
pipe fixed  to  the  side  of  a  small  piece  of  sponge.  In  my  pre- 
parations, these  terminating  tubes  of  the  bronchiae,  the  size  of 
bristles,  are  seen  very  distinctly;  but  there  is  no  appearance 
of  the  penicillous  arrangement,  which  would  be  apparent  if 
each  air  cell  had  its  own  specific  branch  of  the  bronchia  running 
to  it. 

Besides  the  ramifications  of  the  bronchiae,  the  substance  of  the 
lungs  is  composed  of  numerous  blood  vessels  and  lymphatics,  and 
is  well  supplied  with  nerves. 

The  blood  vessels  are  of  two  kinds,  the  pulmonary  and  the 
bronchial.  The  pulmonary  artery,  coming  from  the  right  ven- 
tricle of  the  heart,  divides  under  the  arch  of  the  aorta  into  two 


144  ORGANS  OP  RESPIRATION. 

large  branches :  one  for  the  right  lung,  and  the  other  for  the  left. 
The  right  branch  is  larger  than  the  left.   Each  of  these  branches 
havkig  reached  the  upper  part  of  the  root  of  its  respective  lung, 
begins  there  to  distribute  itself  in  large  trunks,  which  divide  and 
Subdivide  throughout  the  substance  of  the  lung.    The  terminating 
branches  finally  become  capillary,  and  ramify  in  the  parietes  of 
the  fine  cells,  where  the  blood  which  they  carry,  from  being  dark- 
coloured  and  venous,  is  so  altered,  as  to  have  the  arterial  quali- 
ties restored  to  it,  and  to  become  of  a  bright  red.     From  the  ul- 
timate branches  of  the  pulmonary  artery,  arise  the  first  branches 
of  the  pulmonary  veins.     These  are  successively  accumulated 
into  two  large  trunks  on  each  side,  which,  issuing  at  the  lower 
part  of  the  root  of  the  -lung,  go  to  qpen  into  the  left  auricle  of 
the  heart*     It  has  been  remarked  by  Mr.  Bqyer,  that  the  two 
pulmonary  veins  are  less -capacious  than  the  pulmonary  artery  of 
the  same  side,  in  which  they  manifest  a  peculiarity  of  blood  ves- 
sels, differing  from  what  exists  in  other  parts  of  the  body.     The 
pulmonary  artery  and  veins  are  distributed  in  company  with  the 
branchiae.    From  the  observations  of  Professor  Mayer,  it  ap- 
pears that  valves  exist  in  the  pulmonary  veins,  contrary  to  the 
general  opinion  of  anatomists.     They  are  found  where  smaller 
trunks  join  the  larger  ones,  at  an  acute  angle,  but  there  are  none 
when  they  join  at  a  right  angle.* 

The  second  order  of  blood  vessels,  being  the  bronchial,  also 
consists  in  arteries  and  in  veins,  and  are  for  the  nourishment  of 
the  lungs.  They,  too,  attend  the  branches  of  the  bronchia?.  The 
arteries  pervade  the  substance  of  the  lung  by  innumerable  fine 
branches,  and  anastomose  with  the  pulmonary  arteries.  The 
bronchial  veins  also  anastomose  with  the  pulmonary  veins,  but, 
finally,  come  out  in  small  trunks  from  -the  root  of  the  lung,  and 
empty  into  the  vena  azygos. 

The  Lymphatics  of  the  lungs  are  numerous ;  after  traversing 
the  black  bronchial  glands,  those  of  the  left  side  empty  into  the 
thoracic  duct,  and  those  of  the  right  into  the  large  lymphatic 
trunk  coming  from  the  right  upper  extremity. 

The  nerves  come  principally  from  the  par  vagum.  Some  of 
them  are  distributed  with  the  bronchia,  and  may  be  traced  ea>si- 

*  Am.  Med.  Jour.  vol.  in.  page  186. 


THE  LUNGS.  145 

ty  far  along  its  branches,  forming  beautiful  anastomoses  around 
them :  their  texture  there  resembles  much  that  of  the  sympathe- 
tic :  they  are  thought  to  be,  finally,  spent  upon  the  mucous  mem- 
brane :  others  seem  to  be  more  specifically  appropriated  to  the 
vessels. 

It  will  now  be  understood  that  the  root  of  each  lung  is  formed 
by  the  pulmonary  artery,  the  two  pulmonary  veins,  and  the  bron- 
chia, covered  by  the  pleura,  where  the  latter  extends  from  the 
lung  to  the  pericardium.  The  relative  situation  is  such  that  the 
pulmonary  artery  is  above,  the  bronchia  in  the  centre  and  be- 
hind, and  the  pulmonary  veins  below. 

The  lung  of  the  adult  is  of  a  light  pink  colour,  with  specks  or 
patches  of  black :  in  early  life  there  is  much  less  of  the  latter, 
and  in  advanced  life  it  becomes  more  abundant. 

The  texture  of  the  lung  is  so  light  and  spongy  after  an  animal 
has  once  breathed,  that  its  weight  is  very  inconsiderable  when 
compared  with  its  volume.  Its  cells  are  left  much  distended, 
even  when  the  animal  is  dead ;  and,  notwithstanding  from  its 
unusual  elasticity,  it  expels  a  great  quantity  of  air  when  the  tho- 
rax is  opened,  and  is  thereby  reduced  to  a  third  of  its  size  during 
life ;  yet  it  retains  enough  air  to  make  it  float  in  water,  or  even 
in  spirits  of  wine.  The  quantity  of  air  which  the  lungs  contain 
differs  very  considerably  in  different  individuals,  depending  en- 
tirely on  the  capaciousness  of  the  thorax.  Its  medium  amount 
is  computed  at  one  hundred  and  forty-five  cubic  inches ;  thir- 
ty cubic  inches  of  which  are  changed  at  every  act  of  respira- 
tion. 

Of  the  Pleurte. 

Each  lung  has  a  perfect  covering,  called  Pleura,  t&  which  rt 
is  indebted  for  its  shining  surface.  This  membrane  is  also  re- 
flected from  the  internal  surface  of  the  lung  to  the  adjacent  side  of 
the  pericardium,  and  is  then  spread  over  the  interior  periphery 
of  that  half  of  the  thorax  to  which  it  belongs,  by  lining  the  ribs 
and  intercostal  muscles,  and  covering  the  convex  face  of  the 
diaphragm.  There  are,  therefore,  two  pleurae,  each  of  which  is 
confined  to  its  appropriate  half  of  the  thorax,  so  as  to  line  its 
cavity  and  to  cover  its  lung.  The  pleura,  as  other  serous  mem- 
branes, is  a  thin  membranous  sac.  Its  circumference  is  entire, 


146  ORGANS  OF   RESPIRATION". 

like  that  of  an  inflated  bladder;  there  is,  therefore,  no  point  or 
line  at  which  one  may  exclusively  begin  an  account  of  its  course 
and  attachments.  To  commence,  however,  at  the  sternum;  the 
pleura  goes  thence  outwardly  to  line  the  lateral  parietes  of  the 
thorax,  as  formed  by  the  cartilages  of  the  ribs,  the  ribs  them- 
selves, and  the  intercostal  muscles.  In  this  way  it  may  be 
traced  around  to  the  dorsal  vertebras,  and  over  the  convex  sur- 
face of  the  diaphragm.  In  proceeding  along  the  first  rib,  which 
is  very  oblique,  it  forms  a  sort  of  bulging  bag,  which  projects 
towards  the  trachea,  lines  the  lower  part  of  the  scalenus  an- 
ticus  muscle,  and  receives  the  upper  extremity  of  the  lung. 
The  pleura,  having  reached  the  dorsal  vertebrae  from  the  ribs, 
passes  from  their  sides  forwards  to  the  posterior  part  of  the  pe- 
ricardium, a  very  small  portion  of  which  it  covers.  It  then 
goes  upon  the  posterior  face  of  the  pulmonary  vessels  and  of 
the  bronchia  to  the  lung;  and  applies  itself  closely  to  the  latter. 
It  then  covers  the  part  of  the  lung  posterior  to  the  pulmonary 
vessels,  and  continues  to  advance  along  the  rounded  surface  of 
the  lung,  to  its  anterior  margin:  it  then  passes  over  the  internal 
surface  of  the  lung,  which  is  anterior  to  the  pulmonary  vessels. 
It  afterwards  covers  the  front  of  the  pulmonary  vessels  and  of 
the  bronchia,  and  gets  in  a  very  short  space  to  the  pericar- 
dium. It  then  passes  forwards  on  the  side  of  the  latter,  and 
having  got  near  its  middle  line,  goes  from  it  to  the  sternum,  and 
reaches  the  line  from  which  the  description  of  its  course  com- 
menced. 

There  is  no  important  difference  between  the  two  pleurae 
either  in  their  mode  of  reflection  or  in  the  organs  to  which  they 
are  attached,  so  that  the  description  of  one  will  apply  to  the 
other.  The  portion  of  each  pleura  covering  the  lung  is  called 
Pleura  Pulmonalis,  and  that  portion  which  lines  the  thorax  is 
the  Pleura  Costalis.  A  duplicature  of  the  pleura  commences  at 
the  inferior  margin  of  the  pulmonary  veins,  and  descending  as 
far  as  the  diaphragm,  attaches  the  inferior  portion  of  the  poste- 
rior margin  of  each  lung  to  the  side  of  the  pericardium  in  front  of 
of  the  vertebrae.  This  duplicature  is  the  Ligamentum  Pulmo- 
nis.  It  is  longer  on  the  left  lung  than  on  the  right,  by  reason 
of  the  greater  vertical  diameter  of  the  former. 

From  what  has  been  said  it  will  now  be  readily  understood, 


THE  LUNGS,  147 

that  the  whole  cavity  of  the  thorax  is  divided  vertically  into 
two  halves,  by  that  portion  of  the  two  pleurae  which  advances 
from  the  spine  towards  the  sternum.  This  septum  is  called  the 
Mediastinum,  and  the  heart,  enveloped  by  the  pericardium,  is 
placed  in  its  centre,  and  separates  the  two  pleurae  widely  apart. 
It  has  been  found  useful  by  anatomists,  for  descriptive  purposes, 
to  subdivide  the  mediastinum  into  three  portions  or  regions. 
One,  passing  from  the  front  of  the  pericardium  to  the  posterior 
face  of  the  middle  line  of  the  sternum,  is  the  Anterior  Medias- 
tinum; another,  passing  from  the  posterior  face  of  the  pericar- 
dium to  the  dorsal  vertebrae,  is  the  Posterior  Mediastinum;  and 
a  third,  which  is  within  the  circuit  of  the  first  ribs,  is  the  Supe- 
rior Mediastinum.  This  division,  though  evidently  arbitrary, 
is  indispensable  to  a  correct  account  of  the  relative  situation  of 
very  important  organs  placed  between  the  two  pleurse. 

1.  The  Anterior  Mediastinum  is  less  important  than  the  other 
two;  the  portions  of  the  two  pleurae  of  which  it  consists  are  al- 
most in  contact,  and  contain  between  them  some  loose  cellular 
substance  by  which  they  adhere  together,  and  by  cutting  through 
which,  after  a  longitudinal  section  of  the  sternum,  they  are 
easily  separated  from  one  another.     The  upper  part  of  this  sep- 
tum contains  the  remains  of  the  thymus  gland;  its  lower  part 
leaves  the  middle  line  of  the  sternum,  and  inclines  to  the  left 
side;  and  when  the  sternum  is  narrow  below,  it  is  attached  to- 
the  anterior  ends  of  the  cartilages  of  the  lower  true  ribs. 

2.  The  Posterior  Mediastinum,  where  it  leaves  the  vertebrae- 
to  reach  the  pericardium,  passes  off  from  a  line  nearer  the  heads 
of  the  ribs  on  the  left  side,  than  on  the  right.     The  descending 
portion  of  the  thoracic  aorta  is  contained  within  this  septum,  on 
the  left  side  of  the  dorsal  vertebrae.     The  oesophagus  is  in  its 
middle  in  front  of  the  vertebrae  above,  but,  in  descending,  it 
crosses  in  front  of  the  aorta,  and  inclines  to  the  left  side  of  the 
dorsal  vertebrae.     The  vena  azygos  occupies  the  right  side  of 
this  mediastinum,  and,  after  ascending,  forms  an  arch  over  the 
root  of  the  right  lung,  and  terminates  by  joining  the  descending 
cava.     The  thoracic  duct,  after  entering  the  thorax  between  the 
crura  of  the  diaphragm,  ascends  in  front  of  the  dorsal  vertebrae 


148  ORGANS  OP  RESPIRATION. 

between  the  aorta  and  the  vena  azygos,  and  behind  the  oesopha- 
gus, till  it  reaches  the  third  dorsal  vertebra;  it  then  inclines  to 
the  left  side,  and  mounting  into  the  root  of  the  neck  near  the 
vertebrae,  it,  finally,  forms  an  arch,  which,  by  advancing  for- 
wards, terminates  in  the  angle  formed  by  the  junction  of  the 
left  internal  jugular  and  subclavian  veins.  The  par  vagum 
nerve,  of  both  sides,  is  also  in  the  posterior  mediastinum. 

3.  The  Superior  Mediastinum  is  bounded  in  front  by  the  up- 
per part  of  the  sternum,  behind  by  the  upper  dorsal  vertebrae, 
and  laterally  by  the  first  ribs.  The  cavity  is  conoidal,  with  the 
base  upwards,  but  is  too  peculiar  to  admit  of  a  rigid  comparison 
with  any  thing  else.  The  pleurae  are  reflected  downwards  from 
the  internal  edge  of  the  first  ribs,  not  abruptly,  but  in  a  round- 
ed bulging  manner,  receiving  there,  as  mentioned,  the  tip  or 
apex  of  the  lungs.  In  order  to  understand  well  the  position  of 
the  pleurae,  it  must  be  borne  in  mind  that  the  upper  rib  is  placed 
very  obliquely  downwards  and  forwards,  at  an  angle  of  about 
forty -five  degrees  with  the  spine;  consequently,  the  pleura,  on 
being  reflected  from  its  whole  internal  edge,  is  much  higher  at 
the  head  of  the  rib  than  it  is  at  the  anterior  extremity  of  the 
same.  This  cavity  is  continuous,  of  course,  with  that  of  the  an- 
terior mediastinum  in  front,  and  also  with  that  of  the  posterior 
mediastinum  behind. 

The  remains  of  the  thymus  gland  are  where  this  cavity  joins 
the  anterior  mediastinum:  a  part  of  the  gland  is,  indeed,  in  each 
of  these  cavities  just  below  the  transverse  vein.  In  contact 
with  the  right  pleura  is  the  descending  Vena  Cava.  The  com- 
mon trunk  of  the  Left  Subclavian,  and  Internal  Jugular,  called 
the  Transverse  Vein,  or  Vena  Innominata,  after  crossing  in  an 
oblique  descent  behind  the  upper  portion  of  the  sternum,  joins 
the  descending  cava  an  inch  above  the  place  where  the  latter 
penetrates  into  the  pericardium.  Behind  the  transverse  vein 
are  the  top  of  the  arch  of  the  aorta,  the  arteria  innominata,  the 
left  carotid,  and  the  left  subclavian.  The  trachea,  with  the  oeso- 
phagus behind  it,  descends  along  the  middle  line  in  front  of  the 
spinal  column.  The  arteria  innominata  crosses  the  front  of  the 
trachea  from  left  to  right  in  ascending;  it  is  in  contact  with  the 
transverse  vein,  and  more  superficial  than  either  of  the  other 


THE  LUNGS.  149 

arteries.  The  phrenic  nerve,  passing  at  the  internal  edge  of  the 
scalenus  anticus,  between  the  subclavian  artery  and  vein,  de- 
scends vertically  in  contact  with  the  pleura.  The  par  vagum 
passes  along  the  side  of  the  trachea,  and  afterwards  behind  the 
corresponding  bronchia,  having  got  into  the  superior  mediasti- 
num between  the  subclavian  vein  and  artery:  its  inferior  laryn- 
geal  branch  encircles  the  subclavian  artery  on  the  right  side,  and 
the  arch  of  the  aorta  on  the  left. 

The  internal  surface  of  the  pleura  is  smooth  and  polished,  and 
is  moistened  and  kept  lubricated  by  an  unctuous  serum,  the  na- 
tural quantity  of  which  is  merely  sufficient  to  allow  the  parts  to 
slide  freely  upon  each  other.  In  dropsy  of  the  chest,  it  is  aug- 
mented frequently  to  such  an  amount  as  to  cause  the  collapse  of 
the  lung  by  pressing  upon  it. 

In  the  cellular  tissue,  between  the  pleura  and  pericardium,  as 
well  as  on  the  diaphragm,  adipose  matter,  in  considerable  abun- 
dance, is  found  in  corpulent  persons  advanced  in  age. 

The  blood  vessels  of  the  pleura  costalis  are  derived  from  those 
which  supply  the  parietes  of  the  thorax,  as  the  intercostals  and 
phrenics.  -They  ramify  in  the  subjacent  cellular  substance,  and 
end  by  exhalent  orifices  on  the  internal  face  of  the  pleura,  from 
which  a  minute  injection  is  poured  out  very  copiously. 


VOL.  II.—  20 


BOOK  VIII. 


OF  THE  CIRCULATORY  SYSTEM. 

FART  I. 

Of  the  General  Anatomy  of  the  Circulatory  System. 

CHAPTER  I. 

GENERAL  CONSIDERATIONS. 

THE  Circulatory  or  the  Vascular  System,  consists  in  a  conge- 
ries of  tubes,  or  cylindrical  canals,  which  convey  the  blood  to 
and  from  every  part  of  an  animal  body,  and  therefore,  enter  into 
the  texture  or  composition  of  almost  every  portion  of  it.  In  all 
animals  there  seems  to  be  a  necessity  for  the  alternate  reception 
and  discharge  of  alimentary  materials ;  in  the  higher  orders,  this 
is  effected  through  the  agency  of  the  vascular  system ;  but  in  the 
most  simple  animals  this  system  does  not  exist,  and  their  whole 
fabric  being  soft  and  permeable,  nutritious  matter  is  introduced 
by  a  direct  absorption,  or  a  species  of  capillary  attraction,  after 
the  manner  of  a  sponge,  or  any  other  porous  body,  and  is  dis- 
charged by  a  process  equally  simple.*  It  is  probable  that  there 
are  some  parts  of  the  human  body  whose  mode  of  nutrition  is 
analogous  to  the  latter ;  as,  for  example,  the  articular  cartilages, 
the  hair,  nails,  and  so  on ;  for  many  observations  tend  to  prove 
that  all  these  organs  have  an  interstitial  circulation. 

*  Hunter  on  the  Blood.    Beclard,  Anat.  Gen. 


152  CIRCULATORY  SYSTEM. 

In  many  animals,  the  blood  is  propelled  from  a  central  point, 
called  the  heart,  to  all  parts  of  the  body,  and  then  returns  again 
to  the  heart.  The  first  movement  is  executed  through  canals 
called  arteries,  and  the  second  through  veins.  It  is  the  most 
simple  scheme  by  which  a  circulation  can  be  carried  on  through 
a  sanguiferous  system,  and  requires  a  heart  with  only  two  cavi- 
ties ;  one  for  propelling  blood  into  the  arteries,  or  departing  tubes, 
and  another  as  a  reservoir  for  receiving  the  blood  of  the  return- 
ing tubes,  or  the  veins.  The  two  cavities  must  be  near  each 
other,  and  have  a  valvular  opening  between  them,  which  will 
permit  the  blood  to  pass  from  the  venous  into  the  arterial  reser- 
voir ;  but  not  from  the  arterial  into  the  venous.  A  circulation  of 
this  simple  cast  is  found  in  fish,  and  in  animals  generally  whose 
respiration  is  effected  on  the  surface  of  the  body ;  but  in  man, 
and  in  other  warm-blooded  animals,  where  respiration  is  carried 
on  interiorly  by  means  of  the  lungs,  their  circulatory  apparatus 
is  double ;  one  part  being  for  the  lungs,  and  the  other  part  for 
the  body  generally. 

In  man,  the  heart  consists  of  four  cavities :  two  auricles,  or  re- 
servoirs of  venous  blood,  and  two  ventricles,  into  which  the  ve- 
nous blood  is  transmitted,  and  which,  in  their  functions,  may  be 
compared  to  the  forcing-pump  of  a  fire-engine.  The  circulation 
is  effected  in  the  following  manner :  The  blood  contained  in  the 
right  auricle  of  the  heart  flows  into  the  right  ventricle,  and  from 
the  latter  it  is  forced  through  the  pulmonary  -artery  into  the 
lungs.  It  returns  from  the  lungs  through  the  four  pulmonary 
veins,  and  is  received  into  the  left  auricle  of  the  heart;  from  the- 
latter  it  flows  into  the  left  ventricle,  and  is  propelled  from  it  into 
the  aorta.  The  aorta  then  distributes  it  through  the  whole  body 
by  an  infinitude  of  small  branches ;  from  the  latter  it  is  collected, 
by  corresponding  veins,  into  two  trunks,  the  Ascending  and  the 
Descending  Cava.  The  ascending  vena  cava  brings  the  blood 
from  the  lower  extremities  and  from  the  abdomen ;  the  descend- 
ing vena  cava  brings  the  blood  from  the  head  and  neck,  the  up- 
per extremities,  and  the  parietes  of  the  thorax.  These  two  trunks 
finally  discharge  the  blood  into  the  cavity  from  which  it  started, 
to  wit,  the  right  auricle.  The  same  round  is  then  renewed,  and 
continues  to  be  repeated  during  the  whole  course  of  life.  It  is 


GENERAL  CONSIDERATIONS.  153 

customary  for  anatomists  to  call  the  route  of  blood  from  the 
right  ventricle,  through  the  lungs,  to  the  left  auricle  inclusively, 
the  lesser  or  the  pulmonary  circulation ;  and  that  which  begins 
at  the  left  ventricle,  goes  through  the  whole  body,  and  ends  in 
the  right  auricle,  the  greater  circulation. 

The  blood  contained  in  the  veins  of  the  greater  circulation,  in 
the  right  auricle  and  ventricle,  and  in  the  pulmonary  artery,  is 
of  a  dark  brown  or  reddish  colour;  while  that  contained  in  the 
pulmonary  veins,  in  the  left  auricle  and  ventricle,  and  in  the 
aorta  and  its  ramifications,  is,  from  being  vivified  by  respira- 
tion, of  a  carmine  or  vermilion  complexion.  The  celebrated 
Bichat  has,  upon  this  difference  of  colour,  founded  his  division 
of  the  whole  circulating  system  into  two  parts;  one  containing 
black  blood,  "  Systeme  vasculaire  a  sang  noire ;"  the  other  red 
blood,  "  Systeme  vasculaire  a  sang  rouge."  This  division 
having  general  physiology  for  its  object,  affords  a  well  marked 
distinction,  suited  to  such  discussions. 

The  lymphatics  also  are  a  part  of  the  circulatory  system,  but 
as  they  do  not  commonly  convey  red  blood,  the  consideration 
of  them  will  be  introduced  subsequently.  "  They  take  a  very 
active  part  in  the  animal  economy,  whether  natural  or  diseased, 
and  seem,  in  many  actions,  to  be  the  antagonists  of  the  arteries; 
while  the  veins  are  much  more  passive,  being  principally  em- 
ployed in  returning  the  blood  to  the  heart."* 

The  largest  vascular  trunks  are  situated  near  the  centre  of  the 
body  and  limbs,  on  the  side  upon  which  flexion  is  accomplished, 
while  those  near  the  surface  are  generally  small.  Most  com- 
monly there  are  one  artery,  one  or  two  veins,  and  several  lym- 
phatics, all  together. 

The  arterial  system  in  its  external  configuration  may  be  com- 
pared to  a  tree,  the  trunk  of  which  is  attached  to  the  heart,  and 
which  by  a  continued  succession  of  divisions  and  subdivisions 
reaches  to  every  part  of  the  body.  There  are  no  means  of  esti- 
mating rigidly  the  collective  area  of  the  branches  in  proportion 
to  that,  of  the  trunk,  but  a  little  observation  on  the  size  of  the 
primitive  branches  will  satisfy  one  of  a  great  excess  on  the  part 
of  the  latter;  and  as  the  rule  is  maintained  throughout,  there 

*  Hunter,  loc.  cit. 


154  CIRCULATORY  SYSTEM. 

must  finally  be  an  immense  disproportion.  We  have  then  rea- 
son to  believe,  that  if  all  the  branches  were  assembled  into  a 
single  cavity,  this  cavity  would  be  somewhat  like  a  cone,  the 
apex  of  which  would  be  next  to  the  heart.  The  same  rule 
holds  in  regard  to  the  venous  system,  it  being  observed,  how- 
ever, that  the  latter  has  two  trunks  connected  with  the  heart  in- 
stead of  one.  The  general  rule  is,  therefore,  established  through- 
out the  vascular  system,  that  the  collective  area  of  the  branches 
is  always  greater  than  that  of  the  trunk  from  which  they  pro- 
ceed.* By  the  same  rule  the  circulation  in  the  branches  must 

*  I  am  indebted  to  a  scientific  friend,  Mr.  Erskine  Hazard,  for  the  following 
computation,  by  actual  measurement,  of  the  arteries,  from  which  it 'appears 
that  in  many  of  them,  at  least,  the  area  of  the  trunks  is  greater  than  that  of 
the  branches  near  them. 

The  Left  Carotid  at  the  Aorta 'is .42 

Its  diameter  at  the  branching  is  .43 

Increase  of  diameter .01 

Its  square  at  the  Aorta  is         -• •   1764 

Each  Carotid  branch  measures  .28,  and  the  sum  of  their  squares 

is        -'---- 1568 

The  difference  of  the  areas  of  the  Carotid  and  its  branches  is  12£  per  cent, 
in  favour  of  the  Carotid. 

Diameter  of  Aorta  near  the  Iliacs .64 

Its  square 4096 

Diameter  of  Left  Iliac .40 

Its  square 1600 

Diameter  of  Right  Iliac  -  -  -  -  -  .37 

Its  square  -------  1369 

Sum  of  their  squares  -        -        -                -     2969 
Aorta  largest  by  nearly  38.  per  cent.,  or 1127 

Square  of  Right  Iliac,  as  above, 1369 

Ditto    External  Iliac -    900 

Ditto    Internal  do.  729 

1629 


GENERAL  CONSIDERATIONS.  155 

be  more  languid  than  in  the  parent  trunks,  as  this  circulation  is 
retarded  both  by  additional  friction  and  by  having  to  fill  up  a 

Branches  largest  by  nearly  19  per  cent,  or  260 


Square  of  Left  Iliac,  as  above, 1600 

Ditto    Internal  Iliac 961 

Ditto    External  do. 900 

1861 

Branches  largest  by  above  16  per  cent.,  or         ....      261 

Great  Sinus  of  Valsalva 13456 

Innominata 2601 

Carotid 1444- 

Subclavian 1024 

Aorta  beyond 3600 


Sinus  greater  than  all,  by 4787 

or  55  per  cent. 

Comparison  of  the  areas  of  the  Iliac  Arteries,  with  that  of  the  Aorta,  half  ah 
inch  above  them,  in  decimals  of  an  inch. 


Greatest  diameters 

Left  Iliac. 
.354 

Aorta. 

.556 

Right  Iliac. 

.390 

Least           do. 

.290 

.410 

.290 

Sum  of  diameters 

.644 

.966 

.680 

Mean  diameters  - 

.322 

.483 

.340 

Their  squares 

-   103684 

233289 

115600 
103684 

Sum  of  the  squares  of  the 
Square  of  the 

Iliacs 
Aorta     - 

. 

219284 
233289 

Aorta  larger  than  the  Iliacs 14005 

or  nearly  6T\  per  cent. 

As  the  areas  of  circles  are  to  each  other  as  the  squares  of  their  diameters,  it 
follows  that  the  aorta  will  contain,  in  a  given  length,  nearly  6^  per  cent,  more 
than  the  two  iliacs;  and,  consequently,  the  blood  must  flow  that  much  faster 


156  CIRCULATORY  SYSTEM. 

larger  canal.*  The  course  of  rivers  exemplifies  this  continual- 
ly; while  confined  to  narrow  channels,  they  rush  tumultuously 
through  them,  but  when  they  begin  to  expand  themselves  into 
capacious  basins,  or  to  be  divided  into  a  multitude  of  smaller 
channels,  the  current  becomes  slower,  and  in  some  cases  imper- 
ceptible, though  the  fact  is  clear,  that  an  equal  volume  of  wa- 
ter is  every  where  descending  in  the  same  period  of  time. 

The  moisture  conferred  upon  all  parts  by  the  circulation  of 
the  blood,  bears  a  sufficient  analogy  to  the  effects  of  irrigation 
upon  ground.  The  water  may  be  conducted  to  the  latter  by  a 
canal,  which  is  finally  divided  into  an  infinitude  of  streamlets, 
which  ramify  every  where,  and  from  the  porosity  of  their  beds 
percolate  laterally,  so  that  the  whole  field,  even  to  its  most 
minute  atom,  is  kept  moistened.  The  streamlets,  afterwards, 
successively  assemble  again  into  a  single  canal,  which  bears  off 
their  superabundant  water.  From  the  nature  of  the  particles  of 
blood,  many  of  them  are  confined  to  their  proper  channels,  and 
can  never  pass  off  by  percolation  into  the  tissue,  through  which 
the  blood  vessels  ramify.  This  may  be  proved  by  the  fact  that 
the  red  globules  of  blood  have  a  diameter  of  from  the  two- 
thousandth  to  the  five-thousandth  part  of  an  inch,  a  size  incon- 
siderable as  it  is,  yet  too  large  to  permit  their  flowing  through 
elementary  fibres  or  atoms;  whereas  serum,  or  the  water  of  the 
blood,  may,  from  the  extreme  fineness  of  the  particles,  be  ab- 
sorbed by  any  tissue  whatever;  a  circumstance  entirely  un- 
questionable, both  from  daily  observation,  as,  for  example,  in 
soaking  a  piece  of  dried  meat  or  a  bone;  and  from  the  reflec- 

through  the  iliacs  than  through  the  aorta,  as  the  same  blood  has  to  be  disposed  of 
in  both  in  the  same  time.  By  this  means  the  power  of  the  heart  is  continued 
much  farther  through  the  system,  as  each  artery  is  large  enough  to  supply  its 
branches  with  but  little  friction.  The  interior  surfaces  of  the  above  iliacs  are, 
together,  2.0806  inches,  while  that  of  the  aorta  is  but  1.518  inches,  or  only  three- 
fourths  of  the  rubbing  surface.  Independently  of  this  circumstance,  it  is  found 
that  there  is  a  greater  difference  in  the  quantities  of  fluids  passing  through  aper- 
tures of  different  sizes  than  there  is  in  the  areas  of  the  respective  apertures. 
This  is  accounted  for  by  there  being  less  friction  between  the  particles  of  fluids 
than  there  is  between  these  particles  and  a  solid;  and,  in  the  larger  apertures,  a 
smaller  proportion  of  the  particles  comes  in  contact  with  the  solid. 

*  It  is  computed  that  the  blood  moves  5233  times  slower  in  the  capillaries  than 
in  the  aorta. 


GENERAL  CONSIDERATIONS.  157 

tion,  that  the  air  itself  will  hold  a  certain  quantity  of  water  in 
solution. 

A  question  then  arises  whether  the  moisture  of  parts  not  sup- 
plied with  red  globules  of  blood,  comes  in  the  living  body  ex- 
clusively from  infiltration  or  from  a  peculiar  set  of  vessels  called 
exhalents,  often  talked  of,  but  as  yet  never  seen?  That  the 
lateral  porosities  of  blood  vessels  are  large  enough  to  allow 
watery  fluids  to  exude,  is  readily  proved  by  injecting  water 
into  the  blood  vessels  of  a  limb,  or  of  any  other  part,  when  the 
latter  invariably  becomes  cedematous.  It  is  in  this  way  even 
possible  to  inundate  a  living  animal,  as  I  have  seen  accomplished 
by  M.  Magendie,  in  Paris.  This  moisture  requires  a  change, 
and  by  continued  additions  would  become  superabundant:  as  it 
has  been  thrown  out  of  the  common  current  of  the  circulation 
and  could  not  be  removed  in  any  other  way,  the  lymphatic  sys- 
tem has,  therefore,  been  added  for  the  purpose.  In  the  lower 
orders  of  animals,  who  are  destitute  of  the  blood  vessels,  the 
interstitial  change  of  moisture  goes  on  without  lymphatics. 

No  part  of  the  human  body  is  exempt  from  moisture,  but 
it  is  furnished  by  smaller  streams,  and  is  also  less  abundant 
in  some  textures  than  in  others;  for  example,  though  blood 
vessels  susceptible  of  conveying  red  blood  do  ramify  through 
tendons  and  ligaments,  yet  they  are  not  numerous,  apparently; 
not  more  so,  indeed,  than  what  is  sufficient  to  keep  up  by  a  de- 
posite  of  serum,  the  flexibility  of  those  parts.  The  vascularity 
of  a  part  "during  life  may  be  ascertained  by  a  simple  process 
after  death,  the  most  vascular  always  lose  proportionately  of 
their  bulk  by  drying;  for  example,  a  muscle  shrinks  more  than 
a  tendon,  a  gland  more  than  a  muscle. 

Besides  the  operation  of  the  lymphatics,  much  of  the  super- 
abundant moisture  is  carried  off  by  insensible  perspiration  and 
evaporation  from  the  surface  of  the  body:  the  latter  process, 
however,  is  much  restrained  by  the  peculiar  character  of  the 
cuticle,  without  which  it  would  become  excessive,  probably 
so  much  so  as  to  exceed  any  supply  of  fluid  through  the 
stomach. 

The  red  globules  of  the  blood,  besides  their  less  obvious  uses, 
VOL.  II.— 21 


158  CIRCULATORY  SYSTEM. 

unquestionably  serve  to  inspissate  the  serous  or  watery  part, 
by  an  intimate  mixture  with  it,  and  thereby  put  a  certain  re- 
straint upon  its  extravasation.  They  also,  from  their  size,  serve 
to  keep  open  the  channels  through  which  the  blood  circulates. 
So  much  associated  is  the  existence  of  red  globules  with  regular 
blood  vessels,  that  there  are  but  few  examples  of  animals  having 
the  former,  without  also  having  the  latter;  whereas,  in  animals 
whose  circulating  fluid  has  not  red  globules,  but  is  a  mere  serum, 
the  entire  destitution  of  regular  blood  vessels  is  very  common, 
and  their  circulation,  if  the  name  be  deserved,  consists  simply 
in  the  transmission  of  moisture  from  one  pore  to  another,  as  oc- 
curs in  a  rag  or  in  a  sponge,  by  mere  capillary  attraction.  Such 
animals  form  a  numerous  class  in  the  chain  of  organized  beings, 
and  have  a  gelatinous  consistence. 

A  remarkable  feature  in  the  vascular  system,  both  arteries 
and  veins,  is  the  disposition  of  trunks  to  run  into  one  another; 
or,  in  other  words,  to  form  an  anastomosis,  whereby,  if  the 
blood  should  be  cut  off  by  one  route,  it  may  still  be  supplied 
through  another.  These  communications  are  frequent  in  the 
head,  in  the  neck,  in  the  thorax,  in.  the  abdomen,  and  in  the 
extremities;  they  exist,  indeed,  wherever  the  blood  vessels  do, 
and  become  more  numerous  as  the  blood  vessels  are  smaller,  or 
more  removed  from  the  centre  of  the  circulation.  It  is  unne- 
cessary here  to  specify  instances,  as  the  more  remarkable  ones 
will  be  mentioned  at  a  proper  time.  But  some  estimate  may 
be  made  of  their  importance,  and  of  the  facility  of  communica- 
tion established  by  them,  when  it  is  remembered  that  cases 
have  occurred  of  obstructed  aorta,  without  the  circulation  ceasing 
in  the  parts  of  the  body  beyond  it:  the  same  has  occurred  to  the 
venae  cavae,  and  to  the  thoracic  duct  also." 

The  extreme  vascular  ramifications  are  called  Capillaries, 
(Vasa  Capillaria,)  and  they  form  the  connexion  between  the 
arteries  and  veins;  or,  by  being  intermediate  to  the  two,  they  are 
the  ultimate  terminations  of  the  arteries,  and  the  commencing 
roots  of  the  veins.  From  the  extreme  tenuity  of  these  vessels,  il  is 

*  lU'cl.ml,  A  int.  Gen. 


GENERAL  CONSIDERATIONS.  159 

impossible  to  indicate  where  the  arteries  terminate  and  the  veins 
begin;  yet  their  continuity  with  the  capillary  system  has  been 
repeatedly  demonstrated,  by  throwing  injections  from  the  one 
into  the  other  system,  and  by  microscopical  observations  made 
on  the  transparent  parts  of  living  animals,  as  the  mesentery  and 
web  foot  of  frogs,  and  the  tail  of  fishes.  These  facts  are  suffi- 
ciently substantiated  by  the  observations  of  Malpighi,  Lewen- 
hoeck,  Prochaska,  and  a  crowd  of  others;  yet  there  are  anatomists- 
who  hold  a  contrary  doctrine,  and  admit  the  parenchyma  of  the 
ancients  (an  indefinable  something,  conceived,  however,  to  be 
spongy)  as  a  point  of  termination  for  the  arteries,  and  of  com- 
mencement for  the  veins. 

Though  the  capillaries  are  all  too  fine  to  be  seen  distinctly 
without  the  microscope,  yet  they  are  found  to  have  several  gra- 
dations of  size.  The  largest  of  them  are  those  which  only  escape 
the  naked  eye,  experience  successive  divisions,  whereby  their 
diameters  are  reduced  from  admitting  a  file  of  several  globules 
of  blood  to  the  caliber  of  one  globule  only.*  The  capillaries 
have  also  frequent  anastomoses  with  one  another.  Sometimes 
the  artery  is  simply  doubled  on  itself,  and  immediately  becomes 
a  vein:  on  other  occasions,  several  capillary  arteries  run  into- 
the  same  vein.  When  these  communications  are  unduly  en- 
larged, they  constitute  what  has  been  called  by  Mr.  John  Belt 
the  aneurism  from  anastomosis,  a  frequent  mark  in  young  chil- 
dren, and  which,  when  it  has  developed  itself  fully,  has  a  spon- 
gy structure  resembling  the  erectile  tissues,  as  the  corpus  caver- 
nosum  penis,  &c.  As  there  is  a  double  circulation,  so  there  is 
a  double  capillaVy  system,  one  for  the  lungs  and  the  other  for 
the  body  generally:  to  these  may  be  added  a  third,  which  exists 
in  the  liver,  between  the  hepatic  extremities  of  the  vena  porta- 
rum  and  the  hepatic  veins. 

The  texture  of  the  capillary  vessels  is  too  fine  to  admit  of 
much  scrutiny,  but  they  appear  as  simple  cylindrical  excavations 
in  the  substance  of  the  part  to  which  they  belong.  It  is  not 
improbable,  that  they  may  be  uninterrupted  continuations  of  the 
internal  coat  of  the  arteries  into  that  of  the  veins.  They  have 
striking  powers  of  extension  and  of  contraction,  and  are  easily 

*  Bcclard,  loc.  cit. 


160  CIRCULATORY  SYSTEM. 

irritated.  An  emotion  of  the  mind,  as  a  sentiment  of  shame  or 
a  feeling  of  resentment,  quickly  causes  those  of  the  face  to  become 
turgid  with  blood.  Local  stimuli  cause  congestions  in  them. 
Cold,  the  application  of  a  weak  acid,  or  fear,  causes  them  to  con- 
tract; though,  under  the  influence  of  the  heart,  they  are  less  so 
than  larger  vessels.  Their  innumerable  channels  cause  a  compa- 
paratively  languid  circulation  of  the  blood  in  them,  for  reasons 
mentioned;  and  by  furnishing  it  with  more  places  of  contact  with 
their  parietes,  put  it  more  under  nervous  influence  than  it  is 
elsewhere. 

These  vessels  are  not  equally  abundant  in  all  the  textures  of 
the  body.  Their  quantity  may  be  ascertained  by  the  redness 
which  a  part  acquires  by  inflammation,  as  well  as  by  fine  injec- 
tions: the  latter  proof  is  preferable,  as,  in  the  former,  it  is  diffi- 
cult to  distinguish  them  from  the  extravasations  which  also  oc- 
cur at  the  same  time.  The  celebrated  injections  of  Ruysch, 
from  their  unusual  minuteness,  induced  him  to  think  that  every 
solid  portion  of  the  body  was  vascular,  yet  he  admitted  that 
some  portions  were  more  vascular  than  others,  thereby  con- 
ceding to  his  antagonists,  that  some  points  at  least  were  not 
formed  by  blood  vessels.  In  the  microscopical  examinations 
on  living  animals,  for  example,  the  frog,  it  is  seen  that  in  their 
feet  the  smallest  capillaries  are  separated  by  distinct  intervals, 
while  in  the  mucous  membrane  of  the  lungs  the  finest  needle 
cannot  have  its  point  inserted  without  opening  several  of  them.* 
The  younger  an  animal  is,  the  more  vascular  are  its  parts:  but, 
on  the  contrary,  as  it  advances  in  age,  the  proportion  of  parts 
not  susceptible  of  injection  increases,  while  the  capillaries  dimi- 
nish in  number.  In  cold-blooded  animals,  it  is  very  evident 
that  some  of  these  capillaries,  or  arterio-venous  communications, 
are  large  enough  to  admit  a  file  of  several  red  globules  abreast, 
while  others  allow  a  single  file  only.  As  a  general  rule,  their 
diameter  may  be  stated  at  from  one  to  five  globules  of  red 
blood.t 

The  nutrition  of  the  body  depends  upon  an  alternation  of  ex- 
halation and  of  absorption;  but  it  is  still  undetermined,  whether 

*  Bcclartl,  Anat.  Gen.  -j-  Beclard,  loc.  cit. 


GENERAL  CONSIDERATIONS.  161 

there  be  any  vessels  whatever  whose  especial  office  is  that  of 
exhalation,  and  which  produce  the  several  secretions  and  ex- 
halations.    If  there  he  such,  they  are  generally  designated  by 
the  term  exhalents,  and  their  diameters  are  too  small  to  transmit 
the  red  globules  of  blood;  their  function  is,  consequently,  to 
give  passage  to  the  serous  particles  only.     This  subject  has  been 
much  agitated  by  anatomists,  and  marshals  the  best  authorities 
on  both  sides.     Among  the  distinguished  advocates  in  the  affir- 
mative, are  Boerhaave,  Haller,  and  Bichat;  and  opposed  to  them, 
are  Prochaska,  Mascagni,  and  Richerand.     The  leading  facts  of 
the  former  are;  The  microscopical  observations  of  Lewenhoeck, 
who  speaks  of  vessels  admitting  only  serous  globules;  the  phe- 
nomena of  inflammation,   which  render  red,  parts  naturally 
white  and  transparent;    the  difficulty  of  conceiving  how  the 
nourishment  of  certain  parts  can  be  maintained,  whose  capillary 
system  of  red  blood  is  so  limited,  in  proportion  to  points  not 
susceptible  of  it.     The  opinion  of  Mascagni  and  others  to  the 
contrary,  is:  That  those  exhalents,  if  they  existed,  should  be 
seen  readily,  inasmuch  as  they  are  within  the  range  of  a  mi- 
croscope, whose  powers  enable  one  to  examine  a  body  much 
smaller  than  a  red  globule  of  blood;  that  injections  should  pe- 
netrate them,  instead  of  being  limited  to  vessels  whose  existence 
is  sufficiently  confirmed  by  examination  in  the  living  state;  that 
if  during  inflammation  they  do  seem  to  be  injected  with  red 
blood,  the  appearance  is  delusive,  and  depends  upon  the  exist- 
ing capillaries  being  dilated  so  as  to  receive  more  red  blood 
than  usual,  upon  the  formation  of  new  vessels,  and  upon  san- 
guineous infiltration;   and,  as  to  membranes  naturally  white,  as 
the  conjunctiva,  the  colour  depends  upon  the'capillaries,  while 
in  a  healthy  state,  being  so  small  that  they  do  not  admit  the  red 
globules  in  a  file  sufficiently  numerous  to  be  perceived  by  tha 
eye,  the  globules  being,  probably,  then  conducted  in  a  series  of 
one  only,  or  in  a  single  file,  like  a  string  of  beads.     It  is,  there- 
fore, much  more  reasonable  not  to  admit  the  existence  of  ves- 
sels which  it  is  very  doubtful  whether  any  one  has  seen. 

When  a  watery  injection  is  pushed  into  a  blood  vessel,  it  in 
a  little  time  shows  itself  as  a  fine  dew  upon  the  surface  of  the 
serous  and  mucou.s  membranes;  in  the  cellular  membrane,  and 
elsewhere.  According  to  many  anatomists,  it  has  gone  through 


162  CIRCULATORY  SYSTEM. 

the  system  of  exhalents,  and,  indeed,  presents  itself  to  sight  in 
very  much  the  same  way  that  exhalation  occurs  in  the  living 
state.  From  the  view  which  has  just  been  taken,  it  becomes 
more  probable,  that  this  perspiration  is  executed  through  the 
interstices  or  pores  of  the  vessels.  In  the  dead  state  it  is  merely 
a  mechanical  result,  a  simple  straining  of  the  fluid;  whereas,  in 
the  living  body  it  is  a  vital  function,  continually  modified  by 
the  peculiar  vital  powers  of  the  organ  or  membrane  where  it 
occurs;  and,  therefore,  presents  itself  under  the  form  of  the  dif- 
ferent secretions.  The  question  of  the  ex'halents  being  a  dis- 
tinct set  of  vessels,  does  not,  however,  appear  to  be  one  of 
much  consequence;  because,  if  they  do  exist,  they  must  be  very 
short  and  very  small;  and  the  assumption  of  their  existence  does 
not  throw  any  light  upon  the  function  of  secretion.  For  the 
latter  is  still  an  incomprehensible  vital  process,  and  as  far  as 
we  have  any  idea  about  it,  it  is  quite  as  easy  to  conceive  of  its 
being  performed  in  the  parietes  of  the  capillaries,  as  in  the 
mouths  of  a  distinct  set  of  vessels,  whose  length  is  too  short  to 
admit  of  an  estimate. 

Besides  the  supposed  existence  of  a  general  system  of  exha- 
lent  vessels,  some  anatomists  have  thought  that  there  was  a  spe- 
cies of  them  acting  particularly  as  nutritive  vessels.  According 
to  Boerhaave,  every  part  must,  therefore,  be  vascular.  Mascag- 
ni  thought  that  the  extreme  arterial  ramifications  are  not  only 
furnished  with  exhaling,  but  also  with  nutritive  porosities ;  and 
that  there  are  every  where  orifices  of  absorbing  vessels,  to  con- 
tain the  nutritive  molecules.  The  theories  of  Bichat  and  of 
Prochaska,  do  not  differ  materially  from  the  latter.  Whatever 
may  be  the  mode  of  existence,  and  the  route  of  nutriment  to  the 
several  parts  of  the  body,  the  operations  involved  are  entirely 
too  subtle  even  for  microscopic  observation.  We,  therefore, 
can  only  understand,  in  a  general  way,  that  the  blood  vessels 
deposite,  and  the  lymphatics  absorb,  by  invisible  avenues  in  the 
cellular  substance,  the  molecules  of  composition  and  of  decom- 
position in  our  organs.*  It  is  to  this  power  that  the  name  of 
vital  force  has  been  given,  and  especially  that  of  the  force  of 
formation,  (nisus  formations.) 

The  arteries,  though  commonly  said  to  be  cylindrical  canals. 

*  Bcclard,  loc.  cit. 


GENERAL  CONSIDERATIONS.  103 

are  not  exactly  so,  but,  as  they  recede  from  the  heart,  increase 
somewhat  in  diameter,  even  where  they  do  not  send  off  any 
branches.  In  this  way  the  arteries  of  the  umbilical  chord  are 
evidently  larger  as  they  get  nearer  the  placenta;  and  the  sper- 
matic arteries  of  a  bull  as  they  get  nearer  to  the  testicle.  Ob- 
servations made  on  the  carotid  arteries  of  the  camel,  and  of  the 
swan,  by  Mr.  Hunter,*  tend  to  prove  the  same  disposition  in 
them.  It  is  probable  th'at  the  rule  extends  to  all  arteries  through- 
out the  system,  but  it  cannot  be  ascertained  with  so  much  cer- 
tainty, because  of  the  close  succession  of  branches  which  they 
send  off. 

Arteries  have  within  themselves  a  power  of  increase  connect- 
ed with  the  exigencies  of  the  part  to  which  they  go :  thus,  the 
uterine  arteries  increase  much  in  their  capacity  during  pregnan- 
cy, while  the  hypogastric,  from  which  they  are  derived,  aug- 
ment inconsiderably,  and  the  primitive  iliacs  not  in  an  appre- 
ciable manner.  In  animals  of  the  deer  kind,  whose  horns  are 
deciduous,  the  same  augmentation  of  arterial  trunks  occurs 
while  the  horn  is  growing.  Tumours  are  supplied  in  the  same 
way.  But  in  all  these  cases,  after  the  exigency  is  passed,  the 
vessels  diminish  to  their  primitive  size. 

With  the  exception  of  the  semi-lunar  valves  at  the  orifice  of 
the  pulmonary  artery  and  of  the  aorta,  there  are  no  others  in 
the  whole  arterial  system.  These  valves  permit  the  blood  to 
pass  in  the  direction  of  the  circulation,  but  not  backwards,  as 
they  are  closed  immediately  upon  the  cessation  of  the  contrac- 
tion of  the  ventricles.  The  tricuspid  valve  of  the  heart,  and 
the  semi-lunar  of  the  pulmonary  artery,  are  naturally  not  so  per- 
fect in  their  closure  as  those  on  the  other  side  of  the  heart,  but 
permit  a  small  quantity  of  blood  to  retrograde.!  As  life  ad- 
vances, the  valves  of  the  aorta  are  much  disposed  to  ossifica- 
tions and  derangements  of  different  kinds,  which  render  them 
much  less  perfect  than  those  of  the  pulmonary  artery. 

*  On  the  Blood  and  Inflammation.  |  Hunter,  loc.  cit. 


104  CIRCULATORY  SYSTEM. 


CHAPTER  II. 

OF  THE  TEXTURE  OF  THE  ARTERIES. 

THE  arteries  are  composed  of  three  coats ;  an  external,  a  mid- 
dle, and  an  internal. 

The  External  Coat,  also  called  Cellular,  is,  in  fact,  condensed 
cellular  substance  formed  into  a  cylinder.  Its  fibres  run  in  eve- 
ry  direction,  so  as  to  be  perfectly  interwoven  with  one  another. 
The  exterior  periphery  of  this  coat  is  continued  into  the  adja- 
cent cellular  substance,  but  its  internal  face  is  united  more  close- 
ly to  the  middle  coat;  not,  however,  so  tightly  as  to  prevent  a 
slight  sliding  of  the  one  upon  the  other,  and  to  forbid  their  easy 
separation  by  a  knife.  Scarpa  is  not  disposed  to  admit  this  as 
one  of  the  coats  of  arteries,  and  says  that  it  only  serves  as  an 
exterior  envelope,  and  retains  them  in  their  places.  This  coat 
manifests  its  fibrous  character  in  not  being  disposed  to  secrete 
fat,  and  is  more  distinct  in  the  large  arterial  trunks.  It  has  con- 
siderable strength  and  elasticity,  both  circularly  and  longitudi- 
nally, and  is  remarkable  for  its  whiteness.  If  an  artery  be  sur- 
rounded by  a  tightly  drawn  ligature,  the  middle  and  the  internal 
coats  will  be  completely  cut  through  by  it,  while  the  external 
coat  remains  entire.  This  coat,  then,  answers  the  purpose  of  a 
strong  investing  fascia,*  in  which  respect  it  may  be  considered 
as  a  sheath  to  the  proper  arterial  structure,  though  the  term 
sheath  is  commonly  applied  to  the  cellular  membrane  on  its 
outer  side. 

The  Middle  Coat  of  the  arteries  is  called  the  Muscular,  the 
Proper,  the  Tendinous,  and  so  on.  It  is  of  a  light  yellowish 
tinge,  and  decreases  continually  in  thickness,  with  but  few  ex- 
ceptions, from  the  heart  to  the  ends  of  the  arteries;  it  is,  how- 
ever, proportionately  thicker  in  the  small  arteries  than  in  the 
large  ones.  Its  fibres  are  circular,  but  do  not  individually  per- 
form the  circuit  of  the  vessel.  They  are  parallel  to  each  other, 

*  Jones  on  Hemorrhage. 


TEXTURE  OF  THE  ARTERIES.  165 

and  adhere  laterally  by  very  slender  ties.  In  the  larger  arte- 
ries, this  coat  may  be  divided  into  several  laminae,  though  the 
division  is  entirely  artificial.  There  are  no  longitudinal  fibres 
whatever  in  it ;  the  consequence  of  which  is,  that  an  artery  di- 
vested of  its  external  coat,  yields  more  readily  in  the  direction 
of  its  length  than  of  its  circumference. 

The  middle  coat  has  a  firmness,  whereby,  even  when  an  ar- 
tery is  emptied,  the  cylindrical  shape  is  still  retained.  Its  cha- 
racter seems  to  be  the  result  of  a  mixture  of  elastic  and  of  mus- 
cular properties  derived  from  a  state  of  tissue  entirely  peculiar ; 
but  which  some  anatomists  have  been  very  desirous  of  ranging 
under  the  head  of  muscles,  others  under  that  of  ligaments,  and 
a  third,  under  both  united.  The  celebrated  John  Hunter,  whose 
observations  were  generally  made  with  the  most  scrupulous  at- 
tention to  perfect  exactitude,  were  often  repeated,  so  as  to  make 
one  confirm  another ;  and  who  has  received  that  sanction  of 
greatness  in  which  one's  posthumous  reputation  becomes  more 
exalted  than  the  living ;  bestowed  much  attention  on  this  sub- 
ject. He  was  induced  to  believe  that  this  middle  coat  was 
formed  by  a  muscular  lamina  internally,  and  an  elastic  one  ex- 
ternally; which  distinction  might  be  rendered  evident  by  cutting 
a  contracted  artery  through  transversely,  when  the  muscular 
coat  would  be  found  projecting  beyond  the  other.  He  acknow- 
ledges, however,  that  he  never  could  discover  the  direction  of 
the  muscular  fibres:  though  he  supposed  them  to  be  oblique,  be- 
cause their  degree  of  contraction  was  greater  than  a  straight 
muscle  could  produce. 

The  elastic  contraction  of  an  artery,  is  manifested  both  in  the 
direction  of  its  length  and  of  its  circumference;  for,  when  put 
upon  the  stretch  in  either  way,  it  has  the  ability  of  returning  to 
its  original  dimensions  after  the  distending  force  ceases.  The 
Muscular  contraction,  however,  only  occurs  in  the  circumference, 
and  not  at  all  in  the  length:  by  it  the  caliber  of  arteries  is  re- 
duced to  a  very  small  diameter,  if  an  animal  be  slowly  bled  to 
death.  If,  in  this  contracted  condition,  an  artery  be  slit  open 
longitudinally,  the  elastic  coat  will,  at  the  cut  margin,  project 
beyond  the  other,  which  Mr.  Hunter  considers  as  another  way 
of  ascertaining  the  existence  of  the  two  tunics.  But  if  this  same 
artery  be  then  stretched  transversely,  the  muscular  coat  will 
VOL.  II.— 22 


166  CIRCULATORY  SYSTEM. 

project  beyond  the  other ;  for  the  reason,  that  if  a  muscle,  after 
death,  be  elongated  by  force,  it  has  no  power  of  returning  from 
that  state,  but  will  remain  precisely  as  it  is:  whereas,  elasticity 
being  a  property  of  matter  enjoyed  quite  as  fully  in  the  dead  as 
in  the  living  state,  the  elastic  coat  of  the  artery  returns  to  the 
medium  condition. 

Mr.  Hunter,  with  a  view  of  satisfying  himself  on  these  several 
points,  had  a  horse  bled  to  death,  so  as  to  obtain  the  vessels  at 
their  minimum  of  contraction.  A  circular  section  of  the  aorta 
measured,  at  first,  five  inches  and  a  half,  and,  on  being  stretched, 
it  lengthened  to  ten  inches  and  a  half;  being  let  alone,  it  con- 
tracted to  six  inches,  at  which  it  remained  stationary;  the  dif- 
ference between  six  inches  and  ten  and  a  half  was  then  the 
amount  of  its  elastic  power,  while  only  half  an  inch  of  contrac- 
tion was  due  to  the  muscular  stratum,  or,  in  other  words,  an 
eleventh  of  the  whole. 

A  section  of  the  iliac  artery,  measuring  two  inches  in  circum- 
ference, on  being  allowed  to  contract  after  stretching,  measured 
two  and  one-third  inches;  it,  therefore,  gained  one-sixth  the 
amount  of  its  muscular  contraction.  A  section  of  the  axillary 
artery  gained  one-eighth — of  the  carotid,  two-thirds — of  the  ra- 
dial artery,  doubled  its  primitive  extent.  From  all  which  the 
inference  was  drawn,  that  the  power  of  recovery  in  a  vessel  is 
greater,  in  proportion  as  it  is  nearer  the  heart,  but  lessens  as  the 
distance  increases,  which  shows  the  decrease  of  elastic,  and  the 
increase  of  muscular  power. 

The  elastic  coat  gives  a  middle  state  to  an  artery,  or  has  a 
continued  tendency  to  it;  if,  therefore,  the  artery  be  too  much 
dilated,  it  contracts  it,  and  if  it  be  too  much  contracted,  it  dilates 
it,  all  of  which  is  readily  exemplified  by  a  cylinder  of  gum  elastic, 
which,  whether  compressed  or  dilated,  has  only  one  state  of  re- 
pose, to  which  it  immediately  returns  on  being  left  to  itself. 
Mr.  Hunter  supposed,  that  a  certain  degree  of  elasticity  is  con- 
tinued to  the  very  end  of  every  artery,  from  this  quality  being 
better  suited  to  sustain  a  permanent  resistance  than  muscular 
power;  as  a  pipe  of  lead,  from  its  want  of  elasticity,  finally 
becomes  stretched  and  useless  under  the  pressure  of  a  column 
of  water,  whereas,  one  of  iron,  from  being  elastic,  always  re- 
acts efficiently.  It  is  this  elasticity  in  the  arteries,  which 


TEXTURE  OF  THE  'ARTERIES.  167 

causes  the  blood,  at  a  little  distance  from  the  heart,  to  flow 
through  them  in  a  continued  jetting  stream  when  they  are 
opened,  although  it  is  supplied  to  the  aorta  by  interrupted  strokes. 
In  this  way,  as  the  artery  is  more  distant  from  the  heart,  the 
stream  becomes  proportionately  regular. 

"  The  muscular  power  of  an  artery  renders  a  smaller  force 
of  the  heart  sufficient  for  the  purposes  of  circulation;  for  the 
heart  need  only  act  with  such  force  as  to  carry  the  blood  through 
the  larger  arteries,  and  then  the  muscular  power  of  the  arteries 
takes  it  up,  and,  as  it  were,  removes  the  load  of  blood  while  the 
heart  is  dilating.  In  confirmation  of  this  remark,  it  is  observa- 
ble in  animals  whose  arteries  are  very  muscular,  that  the  heart 
is  proportionably  weaker,  so  that  the  muscular  power  of  the  ves- 
sels becomes  a  second  part  to  the  heart,  acting  where  the  power 
of  the  heart  begins  to  fail,  and  increasing  in  strength  as  that  de- 
creases in  power."* 

The  Internal  Coat  of  the  arteries"  is  designated  by  the  terms 
Nervous  and  Arachnoid.  It  is  continued  from  the  ventricles  of 
the  heart,  in  the  left  one  of  which  it  is  of  unusual  thickness.  It 
is  the  duplication  of  this  membrane  with  some  fibres  interposed, 
that  composes  the  semi-lunar  valves  of  the  aorta  and  of  the  pul- 
monary artery.  Its  internal  face  is  smooth,  polished,  and  moist- 
ened with  a  kind  of  humidity  which  permits  the  blood  to  flow 
through  with  diminished  friction.  In  the  larger  arterial  trunks, 
some  small  longitudinal  wrinkles  are  observable  in  it ;  and  when 
an  artery  has  been  cut  through,  as  in  amputation,  it  is  disposed 
to  retract  in  small  transverse  wrinkles.  It  is,  therefore,  not 
very  extensible,  but  has,  according  to  the  experiments  of  Sir 
Everard  Home,t  a  considerable  degree  of  solidity t and  strength. 

Ossifications  of  this  membrane  are  very  frequent  after  the  age 
of  sixty. 

In  addition  to  the  tunics  mentioned,  cellular  substance,  vessels, 
and  nerves  enter  into  the  structure  of  arteries. 

The  Cellular  Substance  is  not  abundant,  and  serves  principally 

*  Hunter,  loc.  cit. 

f  Transactions  for  the  Improvement  of  Medical  and  Surgical  Knowledge, 
vol.  i. 


168  CIRCULATORY  SYSTEM. 

to  unite  the  sides  of  the  circular  fibres  to  one  another,  and  to 
join  the  internal  to  the  middle  coat. 

The  Vessels  ( Vasa  Arteriarum)  consist  both  in  arteries  and  in 
veins,  and  come  from  the  adjacent  trunks,  instead  of  from  those 
on  which  they  ramify.  They  may  be  made  very  distinct  by  a 
fine  injection,  or  by  laying  them  bare  in  the  living  body ;  when 
in  a  little  time  after  exposure,  they  begin  evidently  to  carry  red 
blood,  and  to  grow  turgid  as  in  inflammation.  The  difference 
in  the  colour  of  the  blood  distinguishes  these  arteries  from  the 
same  kind  of  veins.  Both  arteries  and  veins  may  be  traced  very 
well  into  the  middle  coat,  but  not  upon  the  internal,  though  the 
changes  which  occur  in  the  latter,  from  disease  and  upon  the 
application  of  ligatures,  prove  clearly  that  exhalation  and  ab- 
sorption are  continually  going  on  there.  For  in  inflamed  arte- 
ries, an  exhalation  is  seen  upon  their  internal  surface,  and  when 
a  coagulum  has  been  produced  by  ligature,  it  is  finally  ab- 
sorbed. 

The  Nerves  of  the  arteries,  according  to  Wrisberg  and  Be- 
clard,  are  numerous  and  considerable,  form  around  them  a  plex- 
us resembling  that  of  the  par  vagum  around  the  oesophagus,  and 
follow  them  into  the  interior  of  our  organs,  with  the  exception 
of  the  brain ;  which  has  them  only  to  its  surface.  They  are 
proportionately  more  abundant  in  the  aortic  than  in  the  pulmo- 
nary system;  also  upon  the  smaller  than  upon  the  larger  arte- 
ries. The  arteries  of  the  head,  of  the  neck,  of 'the  thorax,  and 
of  the  abdomen,  are  supplied  from  the  sympathetic  nerve,  while 
those  of  the  extremities  are  supplied  from  the  nerves  of  the  spi- 
nal marrow. 

The  passing  of  the  blood  through  the  arteries  is  accompanied 
with  a  pulsating  motion,  which,  for  the  most  part,  is  exactly 
synchronous  with  the  contraction  of  the  left  ventricle,  and  de- 
pends upon  an  increased  quantity  of  blood  thrown  into  them  at 
the  moment.  The  dilatation  of  the  artery  may  be  both  seen  and 
felt:  "  but  were  we  to  judge  of  the  real  increase  of  the  artery 
by  this,  we  should  deceive  ourselves;  for  when  covered  by  in- 
teguments, the  apparent  effect  is  much  greater  than  it  really  is 
in  the  artery  itself;  for  in  laying  such  an  artery  bare,  the  nearer 
we  come  to  it,  the  less  visible  is  its  pulsation;  and,  when  laid  en- 
tirely bare,  its  motion  is  hardly  either  to  be  seen  or  felt.  This 


TEXTURE  OF  THE  VEINS.  169 

apparent  diastole  of  the  artery  is  augmented  in  proportion  to  the 
solid  matter  covering  it,  whence  tumours  over  large  arteries 
have  considerable  motion  given  to  them,  and  have  often  been 
supposed  to  be  aneurismal.  Arteries,  in  fact,  during  their  dias- 
tole or  dilatation,  increase  much  more  in  length  than  in  width, 
and  are  thrown  into  a  serpentine  course:  instead,  therefore,  of 
the  term  diastole,  it  should  rather  be  called  the  elongated  state."* 
Mr.  Parry,  of  Bath,t  has  denied  that  the  arteries  dilate  at  all 
during  their  diastole:  his  opinion,  however,  is  peculiar,  though, 
in  an  experiment  performed  some  years  ago  upon  the  carotid 
artery  of  a  calf,  its  correctness  appeared  to  me  then  to  be  fully 
proved. 

There  is  no  part  of  the  human  body  which  presents  more  fre- 
quent varieties,  in  different  individuals,  than  the  arteries.  These 
varieties  are  found,  in  their  place  and  manner  of  origin,  in  posi- 
tion, and  in  the  number  of  their  ramifications.  They  are  com- 
paratively rare  in  the  trunks  of  the  first  order,  more  common  in 
those  of  the  second,  and  still  more  usual  in  those  of  the  third  and 
fourth.  From  these  causes,  discrepancies  are  continually  found 
in  the  descriptions  of  the  most  approved  authorities,  and  must 
last  so  long -as  writers  repose  upon  a  partial  experience,  instead 
of  referring  to  what  has  been  most  generally  observed. 


CHAPTER  III. 

OF  THE  TEXTURE  OF  THE  VEINS. 

THE  veins,  from  their  duty  of  receiving  the  blood  in  all  parts 
of  the  body  from  the  extreme  arteries,  and  returning  it  to  the 
heart,  by  successively  collecting  it  into  the  two  venae  cavag,  may 
be  more  appropriately  compared  to  the  roots  of  a  tree,  than  to 
its  branches.  The  variations  in  them  as  well  as  their  anasto- 
moses, are  more  frequent  than  in  the  arteries. 

They  are  more  numerous  than  the  arteries ;  for,  in  addition  to 

*  J.  Hunter,  loc.  cif. 

f  Experimental  Inquiry  on  the  Pulse,  1816—1819. 


170  CIRCULATORY  SYSTEM. 

two  venous  trunks  attending  each  artery  wherever  the  structure 
of  the  part  is  intended  for  locomotion,  as  in  the  extremities,  and 
in  some  places  upon  the  trunk  of  the  body,  there  is  a  very  abun- 
dant class  of  veins  which  pre  superficial  or  subcutaneous,  and 
which,  when  filled  properly  with  injecting  matter,  form  a  fine 
vascular  network  over  the  whole  surface  of  the  body.*  These  su- 
perficial veins,  in  some  places,  form  trunks  even  larger  than  such 
as  attend  the  arteries,  and  especially  in  the  extremities.  Besides 
the  excess  in  number,  the  veins  which  attend  the  arteries  ( Vena 
Comites)  have  a  capaciousness  which,  in  many  cases,  is  double 
that  of  the  latter.  From  these  several  circumstances,  it  results 
that  the  area  of  the  venous  system  vastly  exceeds  that  of  the  ar- 
terial. 

In  some  cases  the  veins  follow  precisely  the  course  of  the  ar- 
teries, one  for  one,  as  in  the  greater  number  of  the  viscera  of 
the  abdomen,  where  they  have  common  points  of  entering  and 
departure.  Sometimes  two  arteries  discharge  into  one  vein,  as 
in  the  penis,  the  clitoris,  and  the  umbilical  chord ;  sometimes 
they  pursue  a  course  entirely  different  from  the  arteries,  as  in 
the  pia  mater.  For  the  most  part  they  are  less  tortuous  than 
the  arteries. 

The  veins,  when  injected,  assume  a  cylindrical  shape,  yet 
they  differ  materially  from  the  arteries,  in  having  much  thinner 
coats,  and  in  being  so  pliable  that  they  collapse  by  their  own 
weight.  In  the  lower  extremities,  however,  near  the  feet  and 
upon  them,  as  the  veins  sustain  the  pressure  of  a  long  column  of 
blood ;  they  have  additional  thickness  and  strength,  so  as  to  ap- 
proximate them  more  to  the  arterial  structure.  This  provision 
will  be  found  occurring  in  most  places  where  they  have  much 
duty  to  perform. 

"  They  are  similar  to  the  arteries  in  their  structure,  being  com- 
posed of  an  elastic  and  muscular  substance :  the  elasticity  pre- 
serves them  in  some  degree  in  a  middle  state,  although  not  so 
perfectly  as  it  does  in  the  arteries.  The  muscular  power  adapts 
the  veins  to  the  various  circumstances,  which  require  the  area  to 
be  within  the  middle  state,  and  assists  the  blood  in  its  motion  to- 
wards the  heart."t 

*  Pauli  Mascagni  Anatom.  Univers.  Pisis,  1823. 
f  Hunter,  loc.  cit. 


TEXTURE  OF  THE  VEINS.  171 

The  External  Coat  is  thinner  and  not  so  strong  as  that  of  the 
arteries ;  in  other  .respects,  the  resemblance  is  sufficiently  close 
not  to  require  any  particular  comment. 

The  Middle  Coat,  near  the  entrance  of  the  larger  veins  into 
the  heart,  is  distinctly  muscular.*  It  is  formed  of  soft  extensible 
fibres,  many  of  which,  when  the  vein  is  held  up  to  the  light,  ap- 
pear longitudinal,  while  the  most  internal  are  circular:  there  are 
difficulties,  however,  in  the  separation  of  these  fibres,  which  pre- 
vent their  course  from  being  accurately  ascertained.  Bichat  and 
Meckel  assert,  that  the  whole  of  them  are  longitudinal,  and  that 
there  are  none  circular. 

This  coat,  in  the  human  subject,  is  much  thicker  in  the  system 
of  the  ascending  than  of  the  descending  cava ;  it  is  also  thicker 
in  the  superficial  than  in  the  deep-seated  veins.  In  some  sub- 
jects it  is  much  better  developed  than  in  others.  In  certain  parts 
of  the  body  it  is  entirely  deficient,  as  in  the  sinuses  of  the  dura 
mater,  and  has  its  place  supplied  by  this  membrane ;  the  same 
deficiency  exists  in  the  sinuses  of  the  bones. 

The  Internal  Coat  is  more  delicate  and  extensible  than  the 
corresponding  one  of  the  arteries,  is  less  liable  to  rupture,  and 
less  disposed  to  ossification.  It  is  thrown  into  a  considerable 
number  of  duplications,  forming  valves.  Each  valve  is  of  a  se- 
micircular shape ;  is  connected  by  its  convex  edge  to  the  vein, 
while  the  straight  edge  is  loose,  and  turned  towards  the  heart. 
When  the  veins  are  injected  backwards,  these  valves  may  be 
forced  in  the  larger  trunks,  and  give  them  a  knotted  appearance. 
The  valves  are  commonly  in  pairs,  but  in  certain  veins,  as  the 
crural  and  the  iliac,  there  are  three  of  them  together ;  very  rare- 
ly do  they  amount  to  four.  In  some  instances  there  is  but  a 
single  one ;  this  arrangement  is  more  frequent  at  venous  orifices, 
as  the  great  coronary  vein  of  the  heart,  the  vena  cava  ascen- 
dens,  the  vena  azygos.  They  are  frequently  found  reticulated  as 
if  they  had  been  lacerated,  whence  it  has  been  supposed  that  the 
fibres  which  cross  the  sinuses  of  the  dura  mater  are  an  elemen- 
tary approach  to  them. 

*  Beclard,  loc.  cit. 


172  CIRCULATORY  SYSTEM. 

The  valves  are  more  abundant  in  the  superficial  than  in  the 
deep-seated  veins,  but  they  do  not  exist  every  where.  There  are 
none  in  the  branches  of  the  vena  portarum,  excepting  the  vasa 
brevia :  none  in  the  spine,  in  the  umbilical  vein,  the  cervical  veins, 
the  kidneys,  womb,  ascending  and  descending  cava,  or  in  the 
median  vein.  The  valves  are  proportionately  more  abundant  in 
the  lower  extremities. 

From  the  tenuity  of  the  parietes  of  the  veins,  the  blood  may 
be  readily  distinguished  circulating  through  them.  Their  coats, 
like  those  of  the  arteries,  are  vascular,  or  have  the  vasa  vaso- 
rum.  The  arteries  come  from  the  nearest  small  trunks,  while 
the  corresponding  veins  do  not  empty  immediately,  but  second- 
arily, into  the  trunk,  whos«  parietes  they  supply.  They  are  well 
furnished  with  veins. 

Their  elasticity,  both  transversely  and  longitudinally,  is  well 
marked ;  but  they  are  not  so  extensible  in  the  latter  direction  as 
the  arteries,  while  they  are  more  so  transversely.  There  can  be 
no  doubt  of  their  spontaneous  powers  of  contraction,  for  it  is 
abundantly  proved  by  their  diminishing  much  in  volume  upon 
the  application  of  cold ;  moreover,  when  a  venous  trunk,  dis- 
tended with  blood,  is  intercepted  by  two  ligatures,  and  then  punc- 
tured, it  empties  itself  entirely  and  rapidly. 

The  circulation  in  the  veins  is  produced,  in  a  principal  degree, 
by  the  contraction  of  the  heart ;  their  own  contraction  may  also 
favour  this  motion,  as  well  as  lateral  pressure  from  contiguous 
parts.  As  the  movement  of  the  blood  in  the  smaller  arteries  is 
so  uniform  as  to  be  almost  without  pulsation,  so  the  latter  disap- 
pears entirely  in  the  veins.  It  is  not  clear  that  this  circumstance 
depends  exclusively  on  the  friction  experienced  by  the  blood  in 
passing  through  the  capillaries,  but  is  probably  rather  owing,  as 
Mr.  Hunter  has  suggested,  to  the  veins  receiving  their  blood  from 
different  arteries,  some  of  whose  channels  are  more  circuitous 
than  others,  and,  consequently,  their  blood  arrives  at  different 
times.  The  momentum  of  the  heart,  then,  even  if  it  did  impinge 
upon  those  channels,  would  not  be  synchronous  upon  the  venous 
trunk,  but  would  be  divided  in  such  a  way  as  to  produce  a  tre- 
mour  or  confused  motion.  The  larger  veins,  however,  have  near 
the  heart  a  pulsation  during  the  contraction  of  the  auricles, 


THE  BLOOD.  173 

arising  from  the  arrest  of  their  circulation  at  the  moment. 
During  inspiration,  the  vacuum  created  in  the  thorax  hurries  on 
the  blood  to  the  heart,  but  in  expiration  it  is  somewhat  im- 
peded.* 

It  has  sometimes  happened,  that  a  large  vein  near  the  heart 
being  opened  by  an  accident  or  an  operation,  a  strong  inspira- 
tion has  caused  the  introduction  of  air,  which,  being  carried  to 
the  heart,  has  produced  instant  death.  It  lately  occurred  in  Pa- 
ris to  the  celebrated  surgeon  Dupuytren. 


CHAPTER  IV. 


OF  THE  BLOOD. 

THE  Blood,  in  the  human  subject,  and  in  many  animals,  is  of 
a  red  colour.  It  is  about  the  consistence  of  thin  size,  has  a  pe- 
culiar smell,  a  nauseous  and  slightly  saline  taste,  and  is  some- 
what heavier  than  water;  its  specific  gravity  being  about  105> 
and  its  temperature  in  the  living  body  is  from  96  to  98°  of  Fah- 
renheit. Its  quantity  is  variously  estimated  at  from  eight  to  one 
hundred  pounds,  so  that  there  would  seem  to  be  no  very  exact 
means  of  ascertaining  this  point. 

So  long  as  it  continues  to  circulate,  or  while  it  is  still  flowing 
from  an  opened  vessel,  it  has,  to  common  inspection,  the  appear- 
ance of  a  homogeneous  fluid ;  yet,  after  it  has  been  drawn  a  few 
minutes,  and  permitted  to  remain  at  rest,  it  assumes  a  thick  ge- 
latinous condition,  expressed  by  the  term  coagulation,  and  by 

*  This  ancient  observation  has  lately  been  renewed,  with  additional  interest 
and  details,  by  M.  Barry  of  Paris.  See  a  Report  of  MM.  Cuvier  and  Dumeril,  con- 
cerning the  Influence  of  the  Atmosphere  on  the  Circulation  of  the  Blood,  in  the 
Philadelphia  Journal  of  the  Medical  and  Physical  Sciences,  July,  1826.  M.  Bar- 
ry  has  probably  assigned  too  much  importance  to  this  influence,  as  it  is  certain 
that  the  circulation  may  go  on  veiy  well  where  no  vacuum  is  produced  at  inter- 
vals in  the  thorax;  for  example,  in  the  foetus,  in  incubation,  and  in  fish. 

VOL.  II.-23 


174  CIRCULATORY  SYSTEM. 

\vhich  it  ceases  to  be  any  longer  fluid.  The  coagulation  begins 
'on  the  surface  of  the  mass,  and  by  a  thin  pellicle,  which  shows 
itself  in  three  or  four  minutes ;  commonly  at  the  end  of  twenty 
minutes  the  coagulation  is  complete  throughout,  but  this  rule 
varies  according  to  the  state  of  the  body  at  the  moment ;  and 
the  coagulation  is  more  protracted  when  the  quantity  of  blood  is 
large  and  has  been  drawn  through  a  large  orifice,  than  where  it 
is  small,  and  has  been  evacuated  through  a  small  orifice.  This 
change  has  scarcely  taken  place,  when  a  spontaneous  separa- 
tion follows,  whereby  it  is  resolved  into  a  watery  part  called  Se- 
^rum,  and  into  a  thick  condensed  mass  called  Cruor  or  Crassa- 
mentum.  The  serum  first  shows  itself  on  the  surface  of  the  co- 
agulum,  in  small  drops,  which  quickly  increasing  in  number  and 
size,  finally  run  together,  a^id  form  a  mass  of  fluid  exceeding 
considerably  that  of  the  crassamentum.  The  separation  into  se- 
rum and  crassamentum-,  though  sufficiently  evident  after  a  few 
hours,  yet  requires  some  days  for  its  complete  accomplishment ; 
for  the  coagulum  still  continuing  to  contract,  expels  more  and 
more  of  the  serum. 

The  peculiar  complexion  of  the  blood  depends  upon  a  red  co- 
louring matter  consisting  in  globules.  This  matter  does  not  seem 
to  be  an  indispensable  -constituent,  as  many  animals  are  entirely 
deprived  of  it,  and  such  as  naturally  are  possessed  of  it,  may 
"have  its  quantity  very  much  reduced  by  repeated  bleedings.  The 
^colouring  matter  is  generally  an  ingredient  of  the  crassamentum, 
so  that  the  whole  of  the  latter  has  a  red  appearance ;  yet  there 
are  some  conditions  of  the  body  in  which  a  spontaneous  separa- 
tion of  it  takes  place,  more  or  less  completely.  For  example,  in 
inflammatory  diseases  the  blood  does  not  coagulate  so  soon  as  in 
health ;  and  the  red  globules,  from  being  naturally  heavier  than 
the  other  constituents  of  the  crassamentum,  subside  to  its  bottom 
•and  leave  it  of  a  white  semi-transparent  colour.  It  is  this  white 
part  upon  which  depends  the  whole  property  of  coagulating,  and 
which  has  been  called  coagulating  lymph.  We  have,  therefore, 
three  constituents  of  blood  manifested  by  its  own  spontaneous 
'changes ;  the  serum,  the  red  globules,  and  the  coagulating  lymph. 

Coagulation,  contrary  to  popular  opinion,  is  not  assisted  by  cold, 
fout  rather  retarded  by  it :  heat  assists  it.*  If  the  heat  be  raised 

*  Hunter  on  the  Blood.    Hewson. 


THE    BLOOD.  175 

to  120°,  blood  will  coagulate  five  minutes  sooner  than  if  left  at 
its  natural  standard,  and  even  sooner  than  if  its  temperature  ba 
reduced  to  50°.  If  Wood  be  frozen  quickly,  before  it  has  time 
to  coagulate,  on  being  thawed  it  returns  to  the  fluid  state,  and 
will  coagulate  afterwards.  The  contact  of  air  does  not  produce 
coagulation.  Dr.  Physick,  in  order  to  ascertain  this  point  con- 
clusively, took  a  glass  tube,  which  had  a  stop  cock  at  each 
end,  and  attached  one  of  its  ends  to  the  vein  of  a  dog.  A 
current  of  blood  was  then  conducted  through  the  tube,  and 
while  it  was  flowing,  the  far  stop  cock  was  closed,  and  im- 
mediately afterwards  the  other;  thus,  a  column  of  blood  was 
obtained  which  had  not  touched  the  aii\  After  permitting  it 
to  remain  a  proper  time,  the  tube  was  broken  asunder,  and 
the  blood  found  coagulated  as  usual.  Rest  is  not  indispensa- 
ble to  the  process,  for  blood,  if  shaken  in  a  vial,  will  still  co- 
agulate. The  division  of  the  blood  into  small  masses  expe- 
dites coagulation.  Therefore,  when  it  flows  slowly  from  the 
blood  vessels,  falls  from  some  height,  or  runs  for  a  distance 
over  the  surface  of  a  dish,  it  coagulates  sooner  than  under  op- 
posite circumstances.  The  latter  are  then  auxiliary  to  the  blood 
manifesting  the  sizy  coat,  one  of  the  concomitants  of  inflam- 
mation ;  because,  if  the  coagulation  be  very  rapid,  it  will  pre- 
vent the  constituents  of  the  crassamentum  from  separating  from 
one  another,  by  entangling  the  red  globules,  in  the  coagulating 
lymph. 

After  death  the  blood  is  coagulated  in  the  veins,  though  not 
so  perfectly  or  generally  as  is  supposed,  for  there  are  no  sub- 
jects which  do  not  bleed  from  their  large  veins,  when  the  latter 
are  opened. 

There  are  many  modes  of  death  which  prevent  entirely  the 
coagulation  of  the  blood  in  the  vessels,  for  example,  where  life 
is  destroyed  by  a  paroxysm  of  excessive  anger ;  by  electricity ; 
by  lightning ;  by  a  blow  upon  the  stomach ;  by  certain  fevers 
of  a  typhoid  character.  Many  chemical  articles  prevent  its  co« 
agulation  on  being  mixed  with  it. 


176  CIRCULATORY  SYSTEM* 


SECT.  I. — OF  THE  SERUM  OF  THE  BLOOD, 

Serum  is  common  to  the  blood  of  all  animals,  and  is  consi- 
dered, by  Mr.  Hunter,  to  be  more  abundant  in  such  as  have  red 
globules.  It  is,  generally,  of  a  lighter  specific  gravity  than  the 
crassamentum.  I  have,  however,  often  seen  the  latter  floating 
in  it,  which  shows  the  contrary  in  some  instances.  Though  its 
separation  commonly  depends  upon  the  coagulation  of  the  latter, 
yet  that  process  is  not  indispensably  necessary,  as  was  once 
witnessed,  by  Mr.  Hunter,  in  a  lady,  in  whom  the  serum  was 
disengaged  from  the  crassamentum,  while  the  latter  was  yet 
in  a  fluid  state.  The  phenomena  of  dropsy,  also,  prove  the 
same  point. 

Serum,  though  very  fluid,  is  not  so  much  so  as  water.  It  is 
a  light  yellow  or  straw  colour,  varying,  somewhat,  in  different 
subjects.  It  contains  a  large  quantity  of  albumen,  or  matter  re- 
sembling the  white  of  an  egg.  It  also  consists  of  water,  of  soda 
uncombined,  and  of  some  of  the  salts  of  soda,  jthe  presence  of 
all  which  may  be  manifested  in  several  ways.  For  example, 
when  exposed  to  a  heat  of  140  degrees  of  Fahrenheit,  it  becomes 
Opaque,  and  at  160  or  165  coagulates  firmly.  During  this  pro- 
cess, a  great  deal  of  air  is  disengaged  from  it.  It  is  also  coagu- 
lated by  spirits  of  wine,  by  all  the  mineral  acids,  by  corrosive 
sublimate,  and  by  many  other  articles,  all  of  which  prove  the 
presence  of  albumen.  Mr.  Brande  considers  this  liquid  albumen 
as  an  albuminate  of  soda,  with  an  excess  of  its  base,  and  that  its 
fluidity  depends  on  the  excess  of  soda;  when,  therefore,  the  lat- 
ter is  removed  or  neutralized  by  an  acid,  the  albumen  coagu- 
lates. Under  the  action*  of  the  Galvanic  pile,  like  the  influence 
of  heat,  the  soda  produces  mucus,  by  blending  with  a  part  of 
the  albumen ;  and  the  remainder  of  the  latter,  not  being  able  to 
retain  its  fluidity  after  the  abduction  of  the  soda,  coagulates. 

This  mucus  is,  probably,  the  part  which  Mr.  Hunter  speaks 
of  as  retaining  its  fluidity  when  other  portions  of  the  serum  are 
coagulated  by  heat.  It  is  observed  in  meat  either  roasted  or 
boiled,  and  comes  from  it  as  a  thin,  limpid  fluid,  somewhat 
tinged  with  the  red  globules.  The  older  the  animal  is,  the 
greater  is  its  comparative  quantity:  in  lamb,  there  is  scarcely 


COAGULATING  LYMPH  OF  THE  BLOOD.  177 

any  of  it,  whereas,  in  mutton  five  or  six  years  old,  it  is  abun- 
dant ;  the  same  rule  seems  to  hold  in  regard  to  the  human  sub- 
ject This  serosity,  or  mucus,  is  coagulable  by  Gourlard's  Ex- 
tract* 

The  serum  is  not  always  transparent,  but  sometimes  wheyish 
and  thin:  when  it  settles,  it  often  throws  up  a  white  scum  like 
cream.  This  more  frequently  occurs  in  pregnant  women,  though 
it  is  not  confined  exclusively  to  either  sex,  or  to  any  known  con- 
dition of  body.  The  specific  gravity  of  the  globules  composing 
this  scum  varies ;  for  though  it  generally  floats  on  the  surface 
of  the  serum,  it  does  not  always:  it  also  sometimes  swims,  and, 
on  other  occasions,  sinks  in  water.  It  has  been  erroneously 
considered  as  chyle  not  yet  assimilated,  or  as  absorbed  fat  or 
oil.  It  is,  probably,  this  substance  which  presents  itself  under 
the  form  of  microscopic  globules  in  the  coagulum  of  serum ; 
and,  when  serum  has  been  kept  for  several  days,  is  deposited  in 
the  form  of  globules  at  its  bottom.  These  globules  present  a 
singular  motion  of  ascent  and  descent  in  the  serum ;  upon  the 
application  of  heat  to  it  by  holding  it  in  the  hand.  It  is  said 
that  albumen,  coagulated,  presents  a  very  close  resemblance  to 
fibrine.f 

The  presence  of  soda  uncombined  in  the  serum,  is  readily  as- 
certained by  an  infusion  of  red  cabbage,  (Brassica  oleracea,)  or 
the  juice  of  the  flag,  (iris  versicolor,)  which  are  both  made  green 
by  it.  Sulphur  combined  with  ammonia,  is  also  found  in  it. 
Owing  to  the  presence  of  sulphur,  serum  has  the  effect  of  black- 
ening silver  when  left  in  it,  and  also  has  its  power  of  dissolving 
the  oxydes  of  mercury,  iron,  copper,  and  other  metallic  prepa- 
rations. 

SECT.  II. OF  THE  COAGULATING  LYMPH  OF  THE  BLOOD. 

Coagulating  lymph,  or  fibrine,  when  circumstances  are  suita- 
ble for  collecting  it,  freed  from  the  red  globules,  offers  the  ap- 
pearance of  a  semi-transparent  body  of  a  very  light  drab  colour; 
it  is  elastic  and  strong,  and,  when  subjected  to  the  microscope, 
has  the  appearance  of  muscular  fibres,  by  being  composed  of 

*  Hunter,  loc.  cit.  f  Beclard,  loc.  cit. 


178  CIRCULATORY  SYSTEM. 

colourless  globules.  Like  muscle,  it  also,  when  macerated  in 
water,  resolves  itself  into  those  globules  before  it  putrefies. 

If  the  blood,  while  flowing  from  an  animal,  be  collected,  and, 
at  the  same  moment,  stirred  round  and  round  with  a  rough  stick, 
the  fibrine  will  gather  upon  the  latter  in  a  fibrous  form,  so  as  to 
resemble  a  mass  of  entangled  and  knotted  packthread.  The 
fibrine  may  be  afterwards  washed  almost  white,  and,  at  any 
rate,  so  as  to  clear  it  entirely  from  the  red  globules. 

The  fibrine,  when  dried,  loses  greatly  in  its  bulk  and  weight, 
by  the  evaporation  of  the  serum  from  it,  so  that  the  proportion 
which  it  seems  to  bear  to  the  whole  mass  of  blood  is  much  less 
considerable  than  one  would  suppose  from  seeing  it  in  the  sim- 
ple coagulated  state. 

The  coagulating  lymph  of  the  blood  being  common,  probably, 
to  all  animals,  w7hile  the  red  particles  are  not,  we  must  suppose 
it  from  this  alone  to  be  the  most  essential  part;  and,  as  we  find 
it  capable  of  undergoing,  in  certain  circumstances,  spontane- 
ous changes,  which  are  necessary  to  the  growth,  continuance, 
and  preservation  of  the  animal ;  while  to  the  other  parts  we  can- 
not assign  any  such  uses,  we  have  still  more  reason  to  suppose 
it  the  most  essential  part  of  the  blood  in  every  animal."* 


SECT.  III. OF  THE  RED  GLOBULES  OF  THE  BLOOD. 

The  particles  of  blood  upon  which  its  red  colour  depends  are, 
by  a  majority  of  observers,  considered  to  be  globular,  and  while 
the  blood  circulates  they  float  about  in  the  lymph  and  serum. 
They  are  of  the  same  size  in  animals  of  the  same  species,  and 
have  no  tendency  to  run  into  each  other,  as  globules  of  mercury 
would.  They  are  plastic,  by  which  they  can  assume  an  ellip- 
tical shape  when  they  circulate  through  vessels  of  a  very  small 
size. 

According  to  the  microscopical  observations  of  Mr.  Bauer, 
each  globule  is  one  two-thousandth  part  of  an  inch  in  diameter, 
but  Capt.  Kater  does  not  consider  it  to  exceed  one  five  thou- 
sandth part  of  an  inch.t  There  seems,  however,  to  be  a  great 

*  Hunter,  loc.  cit.  f  Phil.  Trans.  1818. 


RED  GLOBULES  OF  THE  BLOOD.  179 

uncertainty  in  these  estimates  of  form  and  of  size,  inasmuch  as 
different  observers  do  not  agree  among  themselves.  Father 
Delia  Torre  considered  them  as  flat  circles  or  rings,  with  a 
perforation  in  the  centre,  while  Mr.  Hewson,  in  ascribing  the 
same  shape,  represented  them  as  hollow  or  vesicular,  with  a  red 
dot  in  the  middle.  Mr.  Bauer,  on  the  contrary,  considers  that 
the  dot,  or  colouring  matter  of  the  globule,  is  placed  upon  its 
periphery.  As  the  colour  is  supposed  to  depend  upon  particles 
of  iron,  Dr.  John  Mason  Good  has  wittily  suggested,  that,  ac- 
cording to  Mr.  Hewson,  we  have  the  wheels  of  life  moving  upon 
iron  axles,  whereas,  according  to  Mr.  Bauer,  they  only  have 
iron  tiers.* 

It  has  been  observed  that  the  red  globules  are  the  heaviest 
part  of  the  mass  of  blood,  and  are,  therefore,  always  disposed  to 
subside  to  the  bottom  of  the  crassamentum,  though,  from  the 
quick  coagulation  of  the  latter,  they  can  seldom  do  it  before  they 
become  entangled  in  it,  and  thereby  fixed  to  a  certain  place. 
They  do  not  invariably  retain  their  form,  but  are  readily  dis- 
solved in  water.  They  are,  of  course,  insoluble  in  serum.  Urine 
does  not  dissolve  them ;  neither  does  a  solution  of  muriate  of  soda, 
of  sal  ammoniac,  Epsom  salts,  nitre,  diluted  sulphuric  or  muria- 
tic acid :  the  latter,  however,  deprives  them  of  colour. 

The  solution  of  red  globules  in  water  is  manifested  by  the  mix- 
ture becoming  of  a  fine  transparent  red,  and  the  process  takes 
place  almost  immediately.  On  the  contrary,  when  the  globules 
refuse  to  be  dissolved,  a  rnuddy  mixture  is  formed.  When  they" 
are  dried  in  serum,  and  afterwards  soaked  again  in  it,  they  do 
not  resume  the  globular  form.  They  have  more  substance  than 
the  coagulating  lymph,  for  they  do  not  lose  so  much  of  their  bulk 
by  drying. 

Notwithstanding  the  doubts  that  have  been  raised  on  the  sub- 
ject, it  seems  now  to  be  very  well  ascertained,  that  iron  is  the 
colouring  principle  of  the  red  globules  of  the  blood,  though  it 
cannot  be  detached  in  the  coloured  state,  owing  to  the  absolute 
necessity  of  using  strong  heat,  or  concentrated  acids  to  destroy 
the  substance  with  which  it  is  combined.  The  iron  is  an  oxide 
with  a  small  quantity  of  the  sub-phosphate,  but  a  knowledge  of 

'*  Study  of  Medicine,  vol.  ii.  p.  25. 


180  CIRCULATORY  SYSTEM. 

this  fact  does  not  enable  the  chemist  to  imitate  red  globules  by 
mixing  these  chemical  substances  with  albumen.  The  process 
by  which  Berzelius  obtains  iron  from  the  blood,  consists  in 
placing  a  clot  of  the  latter  upon  blotting  paper,  whereby  its  se- 
rum is  absorbed.  The  clot  being  afterwards  put  into  water,  its 
colouring  matter  is  dissolved,  while  the  lymph  remains  entire ; 
by  removing  then  the  lymph,  and  evaporating  the  water,  the  co- 
louring matter  is  obtained,  which,  on  being  reduced  to  ashes, 
renders  about  one  to  two-hundredth  part  of  its  weight  in  iron. 

The  chemists  also  inform  us,  that  fibrine,  albumen,  and  the  co- 
louring matter,  all  resemble  one  another  so  closely,  that  they  are 
only  modifications  of  one  and  the  same  substance ;  and  that  each 
of  them  yields,  upon  decomposition,  phosphate  and  carbonate  of 
lime,  though  these  ingredients  cannot  be  detected  by  tests  ap- 
plied to  the  entire  mass  of  blood. 

"  It  is  difficult  to  determine  by  what  means  the  iron,  or  the 
sulphur,  or  the  elementary  principles  of  calcarious  earth,  obtain 
an  existence  in  the  blood.  If  these  materials  were  equally  dif- 
fused throughout  the  surface  of  the  earth,  we  might  easily  con- 
ceive that  they  were  introduced  through  the  medium  of  food. 
But  as  this  is  not  the  case,  as  some  regions,  like  New  South 
Wales,  at  least,  on  this  side  the  Blue  Mountains,  contain  no  lime- 
stone whatever,  and  others,  no  iron  or  sulphur,  while  all  these 
are  capable  of  being  obtained  apparently  as  freely  from  the  blood 
of  the  inhabitants  of  such  regions,  as  from  that  of  those  who  live 
in  quarters  where  such  materials  enter  largely  into  the  natu- 
ral products  of  the  soil ;  it  is,  perhaps,  most  reasonable  to  con- 
clude that  they  are  generated  in  the  laboratory  of  the  animal 
system  itself,  by  the  all-controlling  influence  of  the  living  prin- 
ciple."* 

The  red  globules,  according  to  the  opinion  of  Mr.  Hunter, 
from  not  being  pushed  into  the  extreme  arteries,  where  the 
coagulating  lymph  reaches,  and  from  not  being  found  in  all  ani- 
mals, do  not  contribute  to  the  growth  and  to  the  repair  of  the 
system.  But  they  seem  to  be  connected  with  strength,  in  such 
animals  as  have  them,  as  the  strength  acquired  by  exercise  in-. 

•  Good,  loc,  cit. 


RED  GLOBULES  OF  THE  BLOOD.  181 

creases  their  proportion  and  occasions  them  to  he  carried  abun- 
dantly into  parts  which  previously,  from  a  debilitated  state,  re- 
ceived them  but  partially,  if  at  all.  This  fact  is  well  known  ta 
graziers,  who  keep  their  quantity  in  certain  animals,  as  veal,  re- 
duced by  quietude  and  frequent  bleeding. 

Their  source  is  not  understood,  though  many  conjectures  on 
the  subject  have  been  hazarded.  Mr.  Hunter's  opinion  was, 
that  they  do  not  appear  to  be  formed  in  those  parts  of  the  blood 
already  produced,  but  rather  to  rise  up  in  the  surrounding  parts; 
as,  in  the  incubated  egg,  they  exist  in  the  form  of  a  zone,  com- 
posed of  dots,  previously  to  the  formation  of  vessels.  This  fact 
ought  to  quiet  all  speculations  about  their  coming  from  the 
spleen,  thymus  gland,  and  so  on. 


VOL.  JI.— 24 


BOOK  VIII. 


PART  II. 

Of  the,  Special  Anatomy  of  the  Circulatory  System. 

CHAPTER  I. 

OF  THE  HEART  AND  PERICARDIUM. 

THE  Heart,  (Cor,)  the  centre  of  the  circulation,  is  situated  in 
the  thorax,  between  the  sternum  and  the  spine;  being  bounded 
on  its  sides  by  the  lungs,  and  below  by  the  tendinous  centre  of 
the  diaphragm.  It  is  a  hollow  muscular  organ. 

The  heart  is  of  a  conoidal  shape,  but  flattened  on  the  surface 
which  lies  upon  the  diaphragm.  This  flat  surface  is  on  a  hori- 
zontal line  with  the  lower  end  of  the  second  bone  of  the  ster- 
num; the  base  of  the  cone  is  towards  the  vertebrae,  and  looks 
obliquely  backwards  to  the  right  side,  while  the  apex  is  about 
the  junction  of  the  left  fifth  rib  with  its  cartilage.  Being  placed 
between  the  right  and  the  left  pleura,  in  the  mediastinum,  it  is 
surrounded  by  its  own  proper  capsule  called  the  pericardium. 
Its  common  weight  is  about  six  ounces.  Its  greatest  length,  to 
wit,  that  from  the  apex  to  the  base,  is  about  five  and  a  half 
inches,  four  of  which  are  taken  up  by  the  ventricles:  its  base  is 
about  three  and  a  half  inches  in  diameter. 

The  heart  is  divided  into  four  cavities;  two  auricles  and  two 
ventricles:  the  places  where  the  partitions  are  placed  between 
these  cavities  are  marked  on  the  surface  of  the  heart  by  fissures, 
sufficiently  distinct  to  be  immediately  recognised.  The  two 
auricles  form  the  base  of  the  heart,  the  ventricles  constitute  its 


184  CIRCULATORY  SYSTEM. 

body,  and  the  anterior  end  of  the  left  ventricle,  by  being  ex- 
tended somewhat  beyond  the  right,  forms  the  apex.  The  right 
auricle  and  the  right  ventricle  are  the  two  cavities  which  are 
nearest  to  the  right  side  of  the  body,  while  the  left  auricle  and 
the  left  ventricle  are  the  two  cavities  nearest  to  the  left  side. 
it  will,  however,  be  understood,  from  the  general  observations 
already  made,  that  the  relative  situation  of  these  cavities  is  such 
that  the  right  ones  are  in  front  of  the  others,  and  present  ob- 
liquely forwards  to  the  right  side,  while  those  on  the  left  side 
look  obliquely  backwards  to  the  left  side.  This  position  of  the 
heart  makes  it  encroach  more  upon  the  left  cavity  of  the  thorax 
than  it  does  on  the  right;  from  which  cause  its  pulsations  may 
be  very  easily  distinguished  where  the  left  ribs  join  their  carti- 
lages, while  on  the  right  side  of  the  sternum  there  is  scarcely 
ever  a  perceptible  pulsation. 

The  Pericardium  is  covered  on  its  sides  by  the  pleura,  and 
reposes  on  the  tendinous  centre  of  the  diaphragm,  to  which  it 
adheres  by  close  compact  cellular  substance,  particularly  at  its 
periphery.  When  the  latter  attachment  is  cut  through,  a  sepa- 
ration of  the  remainder  is  easily  effected.  Behind,  the  pericar- 
dium is  opposed  to  the  bronchias  and  the  resophagus. 

The  pericardium  does  not  adhere  to  the  heart,  except  at  the 
base  of  the  latter;  it  is,  therefore,  a  loose  capsule  in,  by  far,  the 
greater  part  of  its  extent.  It  not  only  surrounds  the  heart,  but 
also  the  roots  of  the  large  arteries  and  veins  connected  with  it. 
Thus,  it  includes  the  aorta,  as  high  up  as  the  great  vessels  pro- 
ceeding from  its  arch;  from  the  latter,  it  passes  to  the  trunk  of 
the  pulmonary  artery,  and  also  includes  it,  causing  the  aorta  and 
the  pulmonary  artery  to  lie  close  together.  The  posterior  face 
-of  these  vessels  is  not  covered  so  high  up  as  the  anterior  face. 
The  pericardium  also  invests  the  descending  vena  cava  for  an 
inch  above  its  junction  with  the  right  auricle:  it  likewise  in- 
vests the  trunks  of  the  pulmonary  veins,  and  the  ascending  cava 
as  it  rises  above  the  diaphragm.  The  pouches  which  it  forms 
at  the  base  of  the  heart,  in  passing  from  one  of  these  vessels  to 
another,  are  the  cornua  of  some  anatomists.  It  cannot  be  con- 
sidered as  pierced  for  the  passage  of  these  vessels,  but  is  lost  in- 
sensibly on  their  parietes;  being  continued  into  the  cellular  co- 


THE    HEART.  185 

vering  of  the  arteries,  in  accompanying  them  to  a  great  dis- 
tance.* 

The  pericardium  is  a  double  membrane,  or  consists  of  two 
layers,  an  internal  and  an  external  one.  The  external  mem- 
brane, to  which  the  preceding  description  is  especially  applica 
ble,  resembles  strongly  the  dura  matter,  but  is  thinner;  it  is, 
therefore,  white,  semi-transparent,  fibrous,  and  inelastic.  Its 
thickness  is  greater  on  the  sides  than  below,  where  it  rests  upon 
the  diaphragm,  or  above,  where  it  goes  along  the  great  vessels: 
its  fibres  are  irregularly  disposed  and  interwoven,  but  many 
may  be  traced  longitudinally. 

The  internal  membrane  lines  the  external,  and  gives  the  po- 
lish to  its  cardiac  surface;  it  is  then  conducted  along  the  sur- 
face of  the  several  vessels  that  have  been  mentioned,  to  the 
heart,  over  the  whole  of  which  it  is  spread,  and  adheres  to  it 
by  cellular  substance,  frequently  containing  much  adipose  mat- 
ter: it  also  causes  the  heart  to  have  a  smooth  shining  surface. 
This  is  a  very  delicate  thin  serous  membrane;  and  secretes  a 
fluid,  transparent  and  somewhat  unctuous,  like  that  of  the  joints, 
but  not  so  consistent;  which  lubricates  the  surface  of  the  heart 
and  permits  it  to  play  freely  within  its  pericardium.  This  fluid, 
in  a  natural  state,  seldom  exceeds  a  tea-spoonful,  though  two 
ounces,  or  a  little  more,  are  not  considered  sufficient  evidence 
of  a  pathological  state:  its  augmentation  constitutes  a  dropsy. 

After  death,  we  find  the  pericardium  lying  loosely  upon  the 
heart,  from  the  vacuity,  and  consequently  diminished  bulk  of 
the  latter;  but  while  the  circulation  is  going  on,  the  heart  fills 
and  distends  it.  A  striking  resemblance  is  observable  between 
the  condition  of  the  pericardium  and  the  moveable  articulations. 
Its  external  membrane  corresponds  with  the  strong  fibrous  cap- 
sule that  passes  from  one  bone  to  the  other;  while  the  internal 
is  the  synovial  bag,  which  scarcely  assists  in  the  strength  of  the 
apparatus,  but  secrete's  a  fluid  to  render  motion  easy.  Several 
instances  are  on  record  of  a  total  absence  of  pericardium. 

The  Right  Auricle  (Auricula  Dextra,  anterior]  is  an  oblong 
cuboidal  cavity.  It  is  joined  at  its  posterior  superior  angle  by 

*  Sabatier,  Trait.  d'Anat.  vol.  ii.  p.  284. 


186  CIRCULATORY  SYSTEM. 

the  descending  vena  cava,  and  at.  its  posterior  inferior  angle  by 
the  ascending  vena  cava.  The  structure  of  the  auricle,  between 
these  two  points,  seems  to  be  only  a  continuation  of  that  of  the 
veins.  These  veins  enter  with  a  direction  slightly  forwards,  so 
that  their  columns  of  blood  are  noi  directly  opposed  to  each 
other.  In  front  of  this  continuation  of  U}e  -two  veins,  the  auri- 
cle is  dilated  into  a  pouch  called  its  sinus;  the  upper  extremity  of 
the  latter,  just  in  front  of  the  descending  cava,  is  elongated  into 
a  process  with  indented  edges,  that  hangs  loose,  and  has  some 
general  resemblance  to  the  ear  of  an  animal,  from  which  it  is 
probable  that  the  term  Auricle  has  been  derived. 

The  exterior  surface  of  this  cavity  is  smooth  and  uniform,  but 
its  internal  surface  is  varied  at  several  places.  About  midway 
between  the  orifices  of  the  two  cavae  is  found  a  transverse  pro- 
minence, the  Tuberculum  Lovveri,  which  is  occasioned  by  the 
continuous  structure  of  the  veins  meeting  at  an  obtuse  angle. 
This  cavity  is  separated  from  the  left  auricle  only  by  a  thin  sep- 
tum, which  is  common  to  the  two  auricles.  On  the  septum, 
below  its  middle,  is  a  superficial  circular  depression,  the  Fossa 
Ovalis;  it  is  more  distinct  above  than  below,  and  varies  much 
in  its  dimensions.  It  is  surrounded  by  an  elevated  margin,  com- 
posed of  muscular  fibres,  and  called  its  Annulus,  or  the  Isthmus 
of  Vieussens.  The  septum  of  the  auricles  is  thinner  at  the  fos- 
sa ovalis  than  elsewhere,  and  is  frequently  perforated  by  one  or 
more  foramina.  I  have,  in  several  instances,  seen  a  hole  there, 
large  enough  to  transmit  the  finger.  On  similar,  occasions,  from 
the  valvular  arrangement  of  the  opening,  it  is  probable  that  the 
blood  of  the  two  auricles  is  still  kept  distinct.  The  fossa  ovalis 
always  presents  this  foramen  in  the  foetal  state. 

Just  below  the  fossa  ovalis  is  found  the  Eustachian  valve, 
consisting  in  a  duplication  of  the  lining  membrane  of  the  auri- 
cle. It  is  crescentic,  but  varies  much  in  its  dimensions  and 
shape.  Its  left  extremity  commences  at  the  left  inferior  mar- 
gin of  the  annulus  ovalis;  it  then  extends  itself  along  the  front 
of  the  orifice  of  the  ascending  cava,  where  the  latter  is  con- 
nected with  the  auricle,  but  never  to  an  extent  sufficient  to  ar- 
rest the  circulation  there.  Sometimes  it  is  reticulated  at  its 
margin,  and  half  an  inch  wide;  on  other  occasions,  it  is  scarcely 


THE  HEART.  187 

developed.  Its  loose  edge  looks  upwards,  and  to  the  right  side. 
Its  office  in  the  foetus  is  clearly,  according  to  the  opinion  of  Sa- 
batier,  to  direct  the  blood  of  the  ascending  cava  through  the  fo- 
ramen ovale.  In  the  adult,  it  may,  on  the  general  principle  of 
venous  valves,  oppose  itself  to  the  introduction  of  refluent  blood 
into  the  ascending  cava;  but  this  office  cannot  be  very  impor- 
tant, as  the  valve  is  frequently  scarcely  visible  at  that  age. 

At  the  lower  part  of  the  right  auricle,  just  to  the  left  of  the 
Eustachian  valve  and  very  near  it,  is  the  orifice  of  the  large  co- 
ronary vein  of  the  heart:  it  is  protected  by  a  small  semi-lunar 
valve,  (Valvula  Thebesii,)  formed  also  by  a  duplication  of  the 
lining  membrane  of  the  auricle.  This  orifice  will  admit  a  quill 
of  common  size  very  readily. 

Between  the  right  auricle  and  ventricle  is  a  round  hole,  of 
more  than  an  inch  in  diameter,  for  the  passage  of  the  blood;  it 
is  the  Ostium  Venosum.  Its  margin,  on  the  auricular  side,  is 
smooth  and  rounded. 

The  parietes  of  the  right  auricle  are  formed  by  muscular 
fibres.  On  the  sinus  these  fibres  are  collected  into  small  trans- 
verse fasciculi,  called  Musculi  Pectinati,  from  their  resembling 
the  teeth  of  a  comb.  These  fasciculi,  though  slightly  united 
by  other  fibres,  yet  leave  between  them  deep  interstices,  by 
which  the  external  and  the  internal  membrane  of  the  heart  come 
into  contact.  The  parietes  of  the  auricle  are  about  one  line  in 
thickness.  Its  muscular  structure  is  continued  for  a  short  dis- 
tance, on  the  two  venae  cavse.  There  are  several  orifices  of 
small  veins  on  the  internal  surface  of  this  cavity,  and  in  greater 
abundance  around  the  fossa  ovalis;  they  belong  to  the  system 
of  coronary  vessels,  and  are  the  foramina  Thebesii. 

The  right  Ventricle  ( Ventriculus  Dexter,  anterior.)  The 
general  form  of  this  cavity,  which  receives  the  blood  from  the 
right  auricle,  is  that  of  a  triangular  pyramid,  curved  somewhat 
backwards,  and  having  its  base  downwards.  It  forms  the  great- 
er part  of  the  anterior  surface  of  the  heart,  and  is  about  three 
lines  in  thickness.  It  is  bounded  on  its  posterior  face  by  the 
left  ventricle,  from  which  it  is  completely  separated  by  a  thick 
septum. 

The  internal  surface  of  this  cavity  is  covered  by  muscular  fasci- 


188  CIRCULATORY  SYSTEM. 

culi,  of  very  irregular  shapes  and  dimensions,  designated  under 
the  term  of  Columnse  Carnese:  some  of  the  latter  go  from  one  side 
to  the  other;  others  contribute  to  the  mechanism  of  the  valvu- 
lar apparatus  between  it  and  the  right  auricle;  but  the  greater 
portion  is  employed  in  forming  a  complicated  reticular  texture 
over  the  internal  face  of  the  ventricle.  Those  connected  with 
the  valve  vary  from  four  to  eight  in  number:  they  are  rounded, 
of  different  lengths  and  sizes,  and  detach  from  their  projecting 
extremities  several  small  rounded  tendinous  chords,  (chordae 
lendinese,")  which  are  inserted  into  the  floating  edge  of  the  valve. 
These  chords  sometimes  form  an  intertexture  among  them- 
selves. 

The  Valve,  between  the  ventricle  and  the  auricle,  consists  in 
a  duplicature  of  the  lining  membrane  of  the  ventricle,  arising 
uninterruptedly  from  around  the  ostium  venosum,  at  the  left 
margin,  which  is  there  somewhat  tendinous.  This  Valve  is 
called  the  Tricuspid,  (Valvula  Tricuspis,  Triglochis,)  because 
its  loose  margin  is  divided  into  three  points  or  processes.  One 
of  these  points,  which  is  at  the  anterior  external  margin  of  the 
orifice,  is  much  larger  than  the  other  two  and  more  distinct  in 
its  boundaries.  The  edges  of  these  processes  form  a  sort  of  re- 
ticulated work  along  with  the  adjoining  ends  of  the  tendinous 
chords:  by  this  arrangement  they  are  always  kept  expanded 
and  in  the  cavity  of  the  ventricle. 

The  opening  for  the  pulmonary  artery  is  placed  above  the 
ostium  venosum;  at  this  point,  the  cavity  of  the  ventricle,  in- 
stead of  being  reticulated,  is  made  smooth,  for  the  more  ready 
transmission  of  blood.  The  orifice  of  the  pulmonary  artery  is 
round,  and  about  twelve  lines  in  diameter;  it  is  furnished  with 
three  valves,  called  from  their  shape  Semi-lunar  or  Sigmoid. 
Each  valve  is  a  semicircular  plane,  formed  from  the  lining 
membrane  of  the  artery,  and  attached  to  the  latter  by  its  semi- 
circumference.  The  diameter  of  the  plane  is  loose,  and,  instead 
of  being  straight,  has  each  semi-diameter  of  a  curved  or  fes- 
tooned shape:  in  the  centre  of  its  edge  is  a  small  cartilaginous 
body,  the  Corpusculum  Aurantii,  which,  when  the  valve  is 
thrown  down  by  the  reaction  of  the  artery,  comes  in  contact 
\vith  the  corresponding  bodies  of  the  other  valves,  so  that  they 
serve  as  mutual  abutments.  Between  the  outer  face  of  each 


THE   HEART.  189 

valve  and  the  artery  there  is  a  pouch,  attended  with  a  slight 
dilatation  of  the  artery,  and  called  the  Sinus  Valsalva.  Between 
the  coats  of  each  valve  there  is  an  additional  fibrous  substance, 
for  the  purpose  of  strengthening  it. 

The  Pulmonary  Artery,  immediately  after  its  origin,  goes 
upwards  and  backwards  to  the  under  part  of  the  curvature  of 
the  aorta,  and  there  divides  into  two  trunks,  one  for  each  lung. 
These  trunks  separate  widely,  and  from  the  middle  of  their  fork 
proceeds  a  ligamentous  substance,  the  remains  of  the  Ductus 
Arteriosus  of  the  foetus,  to  the  aorta  posteriorly  to  the  origin 
of  the  left  subclavian  artery.  The  right  Pulmonary  artery  is 
both  longer  and  larger  than  the  left,  and  passing  transversely 
behind  the  aorta  and  the  descending  cava,  then  penetrates  the 
substance  of  the  lung  to  be  distributed  as  mentioned.  The  left 
pulmonary  artery  passes  to  the  lung  in  fn>nt  of  the  descending 
aorta.  Though  the  pulmonary  artery  is  quite  as  large  as  the 
aorta,  its  parietes  are  thinner. 

The  left  Auricle,  (Auricula  Sinistra,  posterior,)  in  the  na- 
tural situation  of  the  heart,  is  concealed  by  the  right  auricle 
and  the  ventricles.  Its  figure  is  more  regularly  quadrangular, 
or  square,  than  that  of  the  right,  and  into  each  of  its  angles  is 
introduced  a  pulmonary  vein,  their  being  two  on  each  side. 
Sometimes,  however,  the  latter  join  together  previously,  so  that 
the  two  have  but  a  common  orifice.  Its  tip,  or  ear-like  portion, 
is  situated  at  the  left  side  of  the  pulmonary  artery,  and  is  longer, 
narrower,  more  crooked,  and  more  notched  at  its  margins  than 
the  corresponding  portion  of  the  right  auricle. 

The  parietes  of  this  cavity  are  muscular,  and  somewhat 
thicker  than  those  of  the  right;  they  are  smooth  and  uniform, 
both  externally  and  internally,  with  the  exception  of  its  ap- 
pendix or  ear-like  portion,  in  which  the  muscu-li  pectinati  pre- 
vail. The  term  sinus  venosus  or  sinus  pulmonalis-  of  anato- 
mists, only  means  that  part  of  the  cavity  into  which  the  pul- 
monary veins  empty.  The  septum  between  the  auricles,  when 
viewed  on  this  side,  has  the  place  of  the  fossa  ovalis  marked 
out  principally  by  its  diaphanous  condition.  Occasionally, 
there  is  some  appearance  of  the  valve  which  once  existed 
there. 

VOL.  IL— 25 


190  CIRCULATORY  SYSTEM. 

At  the  inferior  part  of  the  anterior  side  of  this  cavity  is  found 
the  opening  between  it  and  the  left  ventricle,  also  called  Ostium 
Venosum;  it  is  circular,  and  rather  more  than  an  inch  in  dia- 
meter, resembling  strongly  the  corresponding  orifice  of  the  right 
side  of  thfe  heart. 

The  Left  Ventricle  (Ventriculus  Sinister, posterior)  in  the 
shape  of  its  cavity  resembles  a  long  ovoidal  or  conical  body. 
Its  parietes  are  generally  three  times  as  thick  as  those  of  the 
right  ventricle,  amounting  to  about  eight  lines:  it  is  thicker, 
however,  at  its  inferior  than  at  its  superior  part,  as  it  gradually 
decreases  in  approaching  the  aorta. 

Its  internal  surface  is  arranged  on  the  same  principle  with 
that  of  the  right  ventricle,  being  roughened  by  the  presence  of 
numerous  fleshy  columns  (Columnas  Carneae)  some  of  which 
are  connected  with  the  valvular  apparatus  between  it  and  the 
left  auricle;  others  form  an  intricate  reticular  texture  on  its 
sides,  and  a  few  pass  from  one  side  to  the  other.  As  this  sur- 
face approaches  the  orifice  of  the  aorta,  it  becomes  smooth, 
so  that  no  impediment  may  be  afforded  to  the  passage  of  the 
blood. 

The  Ostium  Venosum,  on  the  side  of  this  cavity,  has  its  mar- 
gin looking  tendinous,  and  furnished  with  a  duplicature  of  the 
lining  membrane  that  surrounds  it.  This  duplication,  by  being 
severed  on  its  loose  edge  into  two  divisions,  obtains  the  name 
of  Mitral  Valve,  (Valvula  Mitralis.)  Its  margin  is  secured 
from  being  pushed  into  the  left  auricle  by  several  chordae  ten- 
dineae,  which  are  attached  by  their  other  extremities  to  four  or 
five  columnar  carneae  projecting  from  the  surface  of  the  ven- 
tricle. The  whole  internal  arrangement  of  this  cavity  indicates 
a  great  increase  of  strength  over  that  of  the  right  side:  in  the 
robustness  of  its  fleshy  columns,  the  number  and  size  of  its  ten- 
dinous chords,  and  the  greater  thickness  of  its  valve.  The 
upper  division  of  the  mitral  valve  is  placed  immediately  below 
the  orifice  of  the  aorta,  and  is  considerably  broader  than  the 
other,  so  that  when  it  opens  to  admit  bloed,  it  is  in  some  mea- 
sure thrown  over  the  aortic  orifice.  There  is  less  of  an  in- 
tertexture  among  the  tendinous  chords  here  than  on  the  right 


THE  HEART. 


191 


side  of  the  heart:  they  cluster  more,  and,  owing  to  the 
breadth  of  the  extremities  of  the  fleshy  columns,  are  more  pa- 
rallel. 

The  Septum  of  the  Ventricles  is  of  considerable  thickness, 
being  formed  almost  exclusively  by  the  continuation  of  the 
fibres  of  the  left  ventricle.  Where  the  large  columnar  carnese 
elevate  themselves  on  its  surface,  its  thickness  is  increased.  Its 
shape  is  somewhat  triangular.  It  forms  a  round  projection  into 
the  right  ventricle,  while  its  other  surface,  which  presents  to 
the  left,  is  concave  to  the  same  degree.  It  is  rather  thinner  as 
is  approaches  the  auricular  septum  than  elsewhere.  Its  fibres 
near  the  apex  are  less  closely  connected  to  each  other. 

The  Orifice  of  the  Aorta  is  furnished  with  three  semi-lunar 
Valves,  which,  in  the  mode  of  their  arrangement,  correspond 
precisely  with  those  of  the  pulmonary  artery.  They  are,  how- 
ever, thicker,  and  the  Corpuscula  Aurantii  are  larger.  The 
Sinuses  of  Valsalva,  attended  with  a  slight  dilatation  of  the  ar- 
tery, exist  in  the  same  way.  Just  beyond  the  margins  of  the 
right  and  of  the  left  valves  are  observed  the  orifices  of  the  two 
'  coronary  arteries.  The  orifice  of  the  aorta  is  somewhat  tendi- 
nous, which  marks  out  the  distinction  of  structure  between  it 
and  the  ventricle.* 

Of  the  Texture  of  the  Heart. 
The  Heart,  with  the  exception  of  the  membrane  which  lines 

*  Mr.  Erskine  Hazard  has  furnished  me  with  the  following-  estimate  on  the 
action  of  these  valves: — 

If  the  diameter  of  the  artery  be  put  =  10,  the 
length  of  the  superior  edge  of  the  valve  will  also 
be  10.  The  arc,  occupied  by  the  valve  will  be 
10.47  =  120°  of  the  circle.  The  valves,  when 
open,  will  either  assume  the  form  at  B,  or  that  of 
the  double  chord  of  60°,  as  at  A.  In  either  case, 
being  .47  shorter  than  the  arc,  they  cannot  come 
in  contact  with  it,  and  must,  therefore,  leave  room 
for  the  blood  to  get  behind  them,  and  depress 
the  valves.  For  the  same  reason,  they  cannot 
close  the  orifice  of  the  coronary  arteries.  The 
chord  of  120°  would  be  8.67. 


192  CIRCULATORY  SYSTEM. 

its  cavities,  and  of  the  serous  lamina  of  pericardium  which  co- 
vers its  surface,  consists  entirely  of  muscular  fibres. 

The  sides  of  the  auricles,  as  stated,  are  much  thinner  than 
those  of  the  ventricles.  In  the  right  auricle,  the  stratum  of 
muscular  fibres  is  uniform  in  its  venous  portion,  but  on  the 
sinus  is  arranged  into  the  parallel  fasciculi  called  the  Musculi 
Pectinati;  a  circular  fasciculus  surrounds  the  orifice  of  the  de- 
scending cava.  In  the  left  auricle,  the  stratunvpf  muscular  fibres 
forms  a  uniform  layer,  and  is  also  thicker  than  on  the  right 
side.  These  fasciculi  commence  on  the  pulmonary  veins  and 
run  transversely  across  the  auricle,  with  the  exception  of  the 
more  deeply  seated,  which  are  irregular,  and  crossed  upon  each 
other.  The  septum  of  the  auricles  is  also  formed  by  a  muscular 
stratum. 

In  the  ventricles,  the  superficial  fasciculi  observe  a  spiral 
course,  and  many  of  those  belonging  to  the  left  ventricle  may 
be  traced  over  the  right;  as  the  fibres  are  more  deeply  situated, 
they  become  shorter  and  more  interwoven.  In  the  septum, 
between  the  ventricles,  the  fibres  of  the  two  cavities  are  much 
interlocked;  but,  with  some  trouble,  may  be  partially  separated. 
The  fibres  of  the  columnse  carneaB  are  too  irregular  in  their 
course  to  admit  even  of  a  general  description.  It  would  appear, 
however,  that  they  are  a  continuation  of  the  superficial  spiral 
fibres  of  the  ventricles  which  penetrate  into  the  interior  of  the 
heart  at  it's  apex,  and  leave  there  a  small  foramen  which  is 
closed  only  by  the  pericardium,  externally,  and  the  lining 
membrane  of  the  heart.  M.  Gerdy  asserts,  that  all  the  fibres 
of  the  heart  arise  from,  and  are  inserted  into,  the  tendinous 
rings  forming  the  ostia  venosa  and  the  orifices  of  the  arteries; 
having  in  the  mean  time  traversed  the  course  which  is  peculiar 
to  the  several  fasciculi,  according  to  their  being  superficial,  in 
the  middle  or  deep-seated.* 

All  the  cavities  of  the  heart  are  lined  by  a  serous  membrane, 
resembling  that  of  the  blood  vessels. 

*  For  a  veiy  detailed  exposition  of  the  Structure  of  the  Heart,  see  Wolff  Act. 
Acad.  Petrop.  1781:;  and  Gerdy,  Journal  Complementaire  du  Diet,  des  Sc.  Med. 
vol.  x.  p.  97. 


THE  HEART.  193 


Of  the  Blood  Vessels  of  the  Heart. 

The  Heart  is  furnished  with  both  arteries  and  veins,  which  be- 
long to  its  nutritious  system. 

The  arteries,  called  Coronary,  arise,  as  observed,  from  the 
trunk  of  the  aorta,  somewhat  above  the  margins  of  the  semi-lu- 
nar valves ;  so  that  when  the  latter  are  applied  against  the  aorta, 
the  orifices  of  these  arteries  are  still  visible. 

The  Right  Coronary  Artery  begins  above  the  anterior  valve, 
and  passes  to  the  right,  beneath  the  pulmonary  artery ;  it  then 
shows  itself  in  the  upper  part  of  the  fissure,  between  the  right  au- 
ricle and  right  ventricle,  and  follows  the  course  of  this  fissure  to 
the  flat  side  of  the  heart.  It  detaches,  as  it  goes  along,  several 
small  branches,  which  come  off  at  right  angles  from  it.  One  set 
of  these  branches  is  distributed  upon  the  right  ventricle,  and  ano- 
ther set  upon  the  right  auricle.  Small  branches  are  also  sent 
from  it  to  the  root  of  the  pulmonary  artery,  and  to.  that  of  the 
aorta. 

The  Left  Coronary  Artery  begins  above  the  left  semi-lunar 
valve.  While  its  root  is  still  obscured  by  the  pulmonary  artery, 
it  divides  into  two  principal  branches,  of  which  the  anterior  runs 
in  the  fissure  on  the  upper  part  of  the  septum  of  the  ventricles  to 
the  apex  of  the  heart,  and  in  this  course  distributes  branches  to 
the  right  and  left  ventricles :  those  to  the  right  anastomose  with 
the  branches  of  the  right  coronary  artery,  which  go  to  the  same 
ventricle.  The  other  branch  goes  along  the  groove,  on  tHe  sep- 
tum, between  the  left  auricle  and  left  ventricle,  and  reaches  the 
under  surface  of  the  heart ;  and  in  this  course  distributes  many 
branches  to  the  left  auricle  and  left  ventricle,  both  on  their  upper 
and  under  surfaces.  It  anastomoses  freely  with  the  branches  of 
the  trunk  that  run  along  the  upper  part  of  the  septum. 

In  consequence  of  the  frequency  of  the  anastomoses  between 
the  two  coronary  arteries,  injecting  matter  thrown  into  one  very 
readily  finds  its  way  into  the  other. 


194  CIRCULATORY  SYSTEM. 

The  Coronary  Veins  receive  the  blood,  which  is  distributed  by 
the  coronary  arteries  through  the  substance  of  the  heart. 

The  Great  Coronary  Vein  ( Vena  Coronaria  Maxima  Cardis)  is 
formed  by  the  union  of  several  trunks,  which  run  from  the  apex 
towards  the  base  of  the  heart.  One  of  them  begins  at  the  apex, 
goes  along  the  superior  fissure  of  the  septum  of  the  ventricles, 
and  then  winds  to  the  left  side,  between  the  left  auricle,  and  the 
left  ventricle :  while  in  the  latter  position,  it  is  joined  by  several 
trunks  corning  from  the  left  ventricle  and  the  left  auricle :  it, 
finally,  empties  into  the  lower  part  of  the  right  auricle,  just  in 
front,  as  mentioned,  of  the  orifice  of  the  ascending  cava ;  being 
there  covered  by  its  own  valve. 

The  Lesser  Coronary  Vein  ( Vena  Coron.  Minor  Cardis)  lies  in 
the  inferior  fissure  of  the  septum  of  the  ventricles.  It  begins  at 
the  apex,  and,  going  backwards,  collects  the  blood  from  the  flat 
surface  of  the  heart,  principally  on  the  right  ventricle.  It  dis- 
charges into  the  great  coronary  vein,  just  before  the  latter  ter- 
minates in  the  auricle. 

Besides  the  preceding  veins,  some  of  a  smaller  size  exist  on 
the  right  ventricle,  and  about  the  root  of  the  aorta  and  pul- 
monary artery,  and  empty  by  several  orifices  into  the  right  au- 
ricle. There  are  also  some  veins  of  a  still  smaller  size,  which 
open  into  all  the  cavities  of  the  heart  by  little  orifices,  called  the 
Foramina  of  Thebesius :  by  Mr.  Abernethy  they  are  considered 
as  being  larger  when  the  lungs  are  diseased.* 

The  Nerves  of  the  Heart  come  principally  from  the  cervical 
ganglions  of  the  sympathetic,  and  follow  the  course  of  the  coro- 
nary arteries.  It  has  been  doubted  whether  these  nerves  are 
actually  distributed  in  the  substance  of  the  heart,  from  the  pre- 
sumption, that  as  they  cannot  be  traced  beyond  the  third  order 
of  branches  of  the  coronary  arteries,  they  are  limited  to  them. 
But,  as  the  ramifications  of  the  sympathetic  are  bestowed  exclu- 
sively upon  the  branches  of  the  circulatory  system,  Meckel  has 

*  London  Philosophical  Transactions,  1798. 


BRANCHES  FROM  THE  ARCH  OF  THE  AORTA.          195 

very  properly  suggested,  that  the  heart  being  also  supplied  with 
nerves  from  the  same  source,  it  follows  that  there  can  be  no  de- 
parture from  the  general  rule,  as  the  heart  is  nothing  more  than 
the  fibrous  portion  of  the  blood  vessels  more  completely  deve- 
loped. 

While  the  circulation  continues,  as  both  auricles  contract  at 
the  same  instant,  whereby  the  blood  is  thrown  into  the  ventri- 
cles, and  as  immediately  afterwards  the  ventricles  contract  si- 
multaneously also,  whereby  the  blood  is  forced  into  the  aorta  and 
the  pulmonary  artery,  so  it  is  the  contraction  of  the  ventricles 
which  causes  the  heart  to  strike  against  the  parietes  of  the  tho- 
rax. For,  as  was  first  pointed  out  by  Dr.  W.  Hunter,  the  blood 
which  is  forced  through  the  large  arteries,  by  extending  them 
diminishes  their  curvature,  or  brings  them  more  into  a  straight 
line,  in  which  effort  the  heart  bounds  up  from  the  tendinous  cen- 
tre of  the  diaphragm.  The  filling  of  the  auricles,  while  this  is 
going  on,  also  assists  in  protruding  the  heart  forwards.  The 
French  anatomists  assert,  that  during  the  contraction  of  the  ven- 
tricles, their  extremity  is  elevated  or  bent  upwards  on  the  body 
of  the  heart,  which  will  also  increase  the  momentum  of  the  stroke 
against  the  thorax. 


CHAPTER  II. 

OF  THE  ARTERIES. 
SECT,  I. THE  AORTA  AND  THE    BRANCHES  FROM  ITS  CURVATURE. 

THE  Aorto  is  the  trunk  of  the  arterial  system.  Having  arisen 
from  the  superior  posterior  end  of  the  left  ventricle,  its  root 
passes  beneath  the  pulmonary  artery,  and  is  entirely  concealed 
in  front  by  it.  Keeping  to  the  right,  it  emerges  from  the  base  of 
the  heart,  between  the  right  auricle  and  the  trunk  of  the  pulmo- 
nary artery,  being  bounded  on  the  right  side  by  the  descending 


196  CIRCULATORY  SYSTEM. 

cava.  Continuing  its  ascent,  it  forms  a  curvature  with  the  con- 
vexity upwards,  and  the  summit  of  which  rises  to  within  eight 
or  twelve  lines  of  the  superior  edge  of  the  sternum.  This  cur- 
vature is  in  front  of  the  third  and  fourth  dorsal  vertebras,  and  its 
direction  is  nearly  marked  out  by  a  line  drawn  from  the  anterior 
extremity  of  the  third  right  rib,  to  the  posterior  end  or  tubercle 
of  the  third  one  on  the  left  side.  In  this  course,  therefore,  the 
aorta  passes  over  the  right  pulmonary  artery,  across  the  left 
bronchia,  and  applies  itself  to  the  left  side  of  the  spine,  about  the 
third  or  fourth  dorsal  vertebra.  It  is  this  curvature  which  ob- 
tains the  name  of  the  Arch  of  the  Aorta,  (Arcus  Aortce.) 

Near  its  origin,  where  the  aorta  is  still  within  the  pericardium, 
it  has  very  commonly,  especially  in  persons  advanced  in  age,  a 
dilatation,  which  is  called  the  great  sinus  to  distinguish  it  from 
the  lesser  sinuses,  or  those  of  Valsalva.  This  dilatation  is  use- 
ful in  diminishing  the  resistance  arising  from  the  curvature  of 
the  aorta,  to  the  current  of  blood,  or  rather  it  is  a  provision  for 
doing  away  with  the  effects  of  this  friction,  whereby  a  larger 
current  of  blood  becomes  a  compensation  for  diminished  velo- 
city. The  ascending  portion  of  the  arch  is  to  the  right  of  the 
vertebral  column,  the  descending  portion  to  the  left,  and  the  mid- 
dle or  horizontal  part  goes  in  front  of  the  trachea. 

The  aorta,  in  its  descent  down  the  thorax,  is  placed  in  the 
posterior  mediastinum,  and  is  covered  on  one  side  by  the  left 
pleura,  while  the  other  side  is  in  contact  with  the  left  surface  of 
the  bodies  of  the  dorsal  vertebras.  At  the  lower  part  of  the  tho- 
rax it  inclines  towards  the  middle  line  of  the  vertebrae,  in  order 
to  reach  the  hiatus  aorticus  of  the  diaphragm,  through  which  it 
penetrates  to  the  abdomen.  In  the  abdomen  it  descends  in  front 
of  the  lumbar  vertebrae,  somewhat  inclined  to  their  left  side ;  and 
at  the  intervertebral  space  between  the  fourth  and  fifth  vertebras 
of  the  loins,  or  somewhat  above  it,  it  ceases,  by  being  divided 
into  two  large  trunks,  the  Primitive  Iliacs ;  one  for  each  lower 
extremity,  and  the  corresponding  side  of  the  pelvis. 

In  this  course  of  the  aorta,  from  the  heart  to  the  loins,  it  first 
gives  off  the  branches  which  supply  the  head  and  the  superior 
extremities :  then,  those  which  supply  the  sides  of  the  thorax ;  af- 
terwards, in  the  abdomen,  it  detaches  the  trunks  which  supply 
the  viscera  and  the  sides  of  the  latter  cavity. 


BRANCHES  FROM  THE  ARCH  OF  THE  AORTA.         197 

The  Coronary  Arteries  are,  strictly  speaking,  the  first  branches 
of  the  aorta,  but  as  they  belong  especially  to  the  heart,  their  de- 
scription is  associated  with  it.  In  all  the  space  between  them 
and  the  superior  convexity  of  the  aortic  arch  no  branches  are 
given  off;  but  as  the  aorta  is  crossing  the  trachea  three  conside- 
rable trunks  arise  from  it,  which  are  distributed  upon  the  head 
and  the  upper  extremities  principally.  They  are,  the  Arteria 
Innominata,  the  Left  Primitive  Carotid,  and  the  Left  Subcla- 
vian. 

The  Arleria  Innominata  is  first  in  its  origin :  in  ascending  from 
left  to  right  in  front  of  the  trachea,  and  behind  the  transverse 
vein,  it  crosses  the  trachea  very  obliquely ;  is  from  an  inch  to 
an  inch  and  a  half,  and  sometimes,  though  rarely,  two  inches 
long,  when  it  divides  into  the  right  subclavian  and  the  right  pri- 
mitive carotid.  The  left  primitive  carotid  arises  from  the  aorta, 
close  upon  the  left  border  of  the  innominata ;  frequently,  indeed, 
from  a  part  of  it.  The  left  subclavian,  though  at  its  origin,  near 
the  left  carotid,  generally  leaves  a  distinct  interval  of  one,  two, 
or  three  lines.  The  relative  situation  of  these  trunks  is  particu- 
larly alluded  to  in  the  account  of  the  superior  mediastinum.  The 
two  last  are,  of  course,  longer  than  the  corresponding  trunks  of 
the  right  side,  by  the  whole  length  of  the  arteria  innominata. 
With  the  exceptions  connected  with  their  mode  of  origin,  the  ar- 
terial trunks  of  the  two  sides  are  exactly  alike,  and  have  the 
same  mode  of  distribution. 

The  Common  Carotid  Artery  (Carotis  Primitiva)  being  a  branch 
of  the  innominata  on  the  right  side,  and  of  the  aorta  on  the  left, 
goes  up  the  neck  to  terminate  just  below  the  cornu  of  the  os  hy- 
oides.  In  the  early  part  of  its  course,  the  right  one  is  more  in- 
clined outwardly  than  the  left,  owing  to  its  origin  from  the  arte- 
ria innominata  in  front  of,  and  to  the  right  side  of  the  trachea; 
whereas,  the  left  ascends  almost  vertically. 

At  the  lower  part  of  the  neck,  just  above  the  sternum  and  the 

clavicle,  the  carotid  is  covered  by  the  sterno-hyoid  and  thyroid 

muscles,  and  by  the  sternal  portion  of  the  sterno-cleido-mastoid. 

It  is  crossed  obliquely  on  a  line  with  the  lower  part  of  the  thy- 

VOL.  II.— 26' 


198  CIRCULATORY  SYSTEM. 

roid  cartilage  or  of  the  larynx,  by  the  omo-hyoid  muscle.  It  lies 
at  the  side  of  the  thyroid  gland,  the  trachea,  the  larynx,  the  oeso- 
phagus, and  pharynx,  in  front  of  the  transverse  processes  of  the 
cervical  vertebrae,  and  the  longus  colli  muscle ;  having  on  its 
outer  margin,  but  somewhat  in  front  the  internal  jugular  vein, 
and  the  pneumogastric  nerve  enclosed  in  the  same  sheath,  and 
the  sympathetic  nerve  behind.  At  the  side  of  the  larynx,  the 
carotid  is  very  superficial,  and,  with  the  exception  of  being 
crossed  by  the  omo-hyoideus  muscle,  it  is  only  covered  by  the 
platysma  myodes  and  the  integuments. 

The  Carotid  having  got  as  high  as  the  space  between  the  os 
hyoides  and  the  thyroid  cartilage,  but  varying  slightly  in  differ- 
ent subjects,  there  divides  into  two  large  trunks,  the  Internal 
Carotid,  which  goes  to  the  brain  and  to  the  eye,  and  the  Exter- 
nal Carotid,  which  is  principally  distributed  upon  the  more  su- 
perficial parts  of  the  head  and  neck.  The  first  of  these  trunks 
is  placed  behind  the  other,  and  bends  outwardly  at  its  root :  it  is 
generally  the  largest  in  infancy,  on  account  of  the  proportionate1 
volume  of  the  brain  at«that  age ;  it  is  also  swollen  at  its  root,  so 
as  to  form  a  sinus  there,  resembling  an  incipient  aneurism.  No 
branch,  except  in  the  abnormous  cases,  is  given  off  from  the  ca- 
rotid between  its  origin  and  bifurcation. 


SECT.  II. OF  THE  CAROTIDS,  AND  THEIR  BRANCHES. 

The  Internal  Carotid,  (Arteria  Carotis  Internet,}  in  the  adult,  is 
smaller  than  the  external,  and  extends  from  the  larynx  to  the 
sella  turcica.  It  ascends  between  the  external  carotid  and  the 
vertebrae  of  the  neck,  being  in  front  of  the  internal  jugular  vein, 
and  having  the  pneumogastric  nerve  at  its  outer  margin :  as  it 
gets  on  a  level  with  the  base  of  the  lower  jaw,  it  is  crossed  ex- 
ternally by  the  digastric  and  the  stylo-hyoid  muscles :  it  is  im- 
mediately afterwards  concealed  in  the  subsequent  part  of  its 
ascent  by  the  ramus  of  the  lower  jaw.  Having  gone  along  the 
most  internal  or  deeply  seated  margin  of  the  parotid  gland  and 
the  styloid  process  of  the  temporal  bone,  at  the  side  of  the  supe- 


CAROTIDS,  AND  THEIR  BRANCHES.  199 

rior  constrictor  of  the  pharynx,  it  then  penetrates  into  the  crani- 
um through  the  carotid  canal  of  the  temporal  bone. 

It  is  slightly  flexed  between  its  origin  and  the  carotid  canal : 
just  before  it  reaches  the  latter  it  curves  upwards  and  forwards. 
The  first  part  of  its  course  through  the  canal  is  vertical,  after- 
wards it  goes  horizontally  forwards ;  and  to  escape  from  the  ca- 
nal it  has  once  more  to  ascend  almost  vertically,  which  brings 
it  to  the  posterior  extremity  of  the  Sella  Turcica.  On  the  side 
of  the  Sella  Turcica  it  again  passes  horizontally  forwards  through 
the  cavernous  sinus ;  and  at  the  anterior  clinoid  process  it  once 
more  ascends,  and  having  penetrated  the  dura  mater,  it  reaches 
the  brain. 

In  this  passage,  through  the  carotid  canal,  it  is  attended  by 
the  upper  extremity  of  the  sympathetic  nerve,  and  gives  one  or 
more  small  branches  to  the  petrous  bone ;  it  also  gives  a  few 
branches  to  the  dura  mater  and  to  the  nerves  about  the  caver- 
nous sinus.  But  for  the  full  exposition  of  the  distribution  of  the 
internal  carotid,  see  the  articles  Brain  and  Eye. 

The  External  Carotid  Artery  (Carotis  Externa]  extends  from 
the  termination  of  the  primitive  carotid,  to  the  neck  of  the  lower 
jaw.  In  the  early  part  of  its  course,  where  it  is  situated  in  front 
of  the  internal  carotid,  and  between  the  pharynx  and  the  sterno- 
mastoid  muscle,  it  is  comparatively  superficial,  being  only  enve- 
loped by  its  sheath,  and  covered  by  the  platysma  myodes  and 
the  skin.  Just  above  this  place  it  is  crossed  externally  by  the  hy- 
poglossal  nerve,  which  detaches  the  descending  branch  along 
the  front  of  its  sheath  and  of  that  of  the  primitive  carotid.  Some- 
what above  this  nerve,  it  is  also  crossed  externally  by  the  digas- 
tric and  the  stylo-hyoid  muscle,  and  lies  there  on  the  side  of  the 
superior  constrictor  muscle  of  the  pharynx,  near  the  tonsil  gland. 
About  its  middle,  it  is  crossed  internally  by  the  stylo-glossus  and 
the  stylo-pharyngeus  muscle ;  it  then  ascends  through  the  sub- 
stance of  the  parotid  gland,  between  the  ramus  of  the  lower  jaw 
and  the  ear,  to  its  termination. 

Several  very  important  branches  are  given  off  from  the  ex- 
ternal carotid ;  they  are  as  follow : 

The  Superior  Thyroid  Artery  (Art.  fhyroidea  Superior)  arises 


200  CIRCULATORY  SYSTEM. 

from  the  external  carotid,  about  a  line  above  its  root,  and  is  dis- 
tributed to  the  larynx  and  to  the  thyroid  gland.  It  goes  at  first 
inwards  and  forwards  on  the  side  of  the  larynx,  being  covered 
by  the  omo-hyoideus  muscle,  and  by  the  platysma  myodes;  it 
then  descends  under  the  sterno-thyroideus  to  the  upper  margin 
of  the  lobe  of  the  thyroid  gland.  In  this  course,  it  performs 
several  flexuosities,  of  considerable  variety  in  different  indivi- 
duals. 

The  Laryngeal  Branch  comes  from  it  near  the  superior  margin 
of  the  thyroid  cartilage;  this  branch  glides  in  between  the  thyreo- 
hyoid  muscle  and  the  middle  membrane  or  ligament  of  the  same 
name;  after  a  short  course,  it  penetrates  the  latter,  and  is  then 
distributed  in  a  great  number  of  small  twigs  to  the  muscles  and 
to  the  lining  membrane  of  the  larynx.  A  small  trunk,  either 
from  the  laryngeal  branch,  or  from  the  thyroid  artery  itself,  is 
spent  upon  the  crico-thyroid  muscle,  and  traversing  the  front 
surface  of  the  middle  crico-thyroid  ligament,  anatomoses  with 
its  fellow:  small  twigs  from  this  branch  penetrate  to  the  interior 
of  the  larynx  through  the  middle  crico-thyroid  ligament.  Some- 
times this  crico-thyroid  ramus  is  superior  in  size  to  the  one 
above,  in  which  case,  it  principally  supplies  the  interior  of  the 
larynx. 

The  Thyroid  Branch  is  the  continuation  of  the  principal  trunk : 
it  penetrates  into  the  substance  of  the  thyroid  gland,  and  divides 
into  two  ramuscles,  one  of  which  goes  along  the  posterior  face 
of  the  lobe  of  the  gland,  and  anastomoses  with  the  inferior  thy- 
roid; the  other  goes  along  the  upper  margin  of  the  gland,  and 
anastomoses  with  its  congener  of  the  opposite  side.  The  thy- 
roidal  artery  is  split  up  into  a  great  many  branches  in  the  sub- 
stance of  the  gland,  it  also  sends  small  branches  to  the  pharynx, 
oesophagus,  and  the  little  muscles  on  the  front  of  the  neck. 

The  Lingual  Artery  (Art.  Lingualis]  comes  from  the  external 
carotid  at  the  distance  of  from  six  to  twelve  lines  above  the  su- 
perior thyroid,  and  goes  to  the  tgngue.  It  is  concealed  in  the 
early  part  of  its  course  by  the.  digastric  and  the  stylo-hyoid  mus- 
cles; it  then  penetrates  the  hyo-glossus  muscle  just  above  the 
cornu  of  the  os  hyoides,  or  goes  between  it  and  the  middle  con- 
strictor of  the  pharynx ;  jt  then  ascends  between  the  hyo-glossus 


CAROTIDS,  AND  THEIR  BRANCHES.  201 

and  the  genio-hyo-glossus  muscle;  advancing  forwards,  it  is 
placed  between  the  latter  and  the  sublingual  gland,  and,  finally, 
reaches  the  tip  of  the  tongue. 

The  lingual  artery  sends  off  the  following  branches.  At  the 
root  of  the  tongue  one  or  more  trunks  arise  from  it  (Dorsales 
Lingua)  which  go  to  the  base  of  this  organ,  the  tonsils,  the  palate, 
and  the  epiglottis.  A  little  farther  on,  this  artery  detaches  an- 
other branch,  (Ramus  Sublingualis,}  which,  advancing  between 
the  mylo-hyoid  and  the  genio-hyo-glossus  muscles,  and  above 
the  sublingual  gland,  detaches  a  great  many  ramifications  to 
these  parts  and  to  the  lining  membrane  of  the  mouth;  it  is  some- 
times a  branch  of  the  facial.  The  Ramus  Raninus,  is  the  con- 
tinuation of  the  lingual ;  it  advances  between  the  lingualis  and 
the  genio-hyo-glossus  muscle,  to  the  tip  of  the  tongue,  distributing 
continually  its  twigs  on  each  margin,  and  ends  there  by  anasto- 
mosing with  the  corresponding  artery  of  the  other  side. 

The  Facial  Artery  (Arteria  Facialis,  Maxillaris  Externa)  arises 
from  the  external  carotid  two  or  three  lines  above  the  lingual, 
and  is  spent  principally  on  the  side  of  the  face  below  the  eye. 
It  is  of  considerable  size,  and  very  tortuous ;  its  root  is  concealed 
by  the  stylo-hyoid  and  the  digastric  muscles,  and  it  is  traversed 
externally  by  the  hypo-glossal  nerve.  It  goes  forward  within 
the  angle  of  the  lower  jaw,  and  above  the  submaxillary  gland, 
but  very  much  connected  with  it:  it  then  mounts  over  the  base 
of  the  maxilla  inferior,  at  the  anterior  margin  of  the  masseter 
muscle,  and  afterwards  shapes  its  course,  in  a  serpentine  manner, 
to  the  internal  canthus  of  the  eye,  passing  between  the  muscles 
and  the  integuments  of  the  face.  In  this  course,  the  fascial 
artery  sends  off  the  following  branches. 

As  it  passes  by  the  submaxillary  gland  it  sends  several  twigs 
to  it:  previously  it  also  sends  several  little  branches  to  the  con- 
tiguous muscles,  as  the  internal  pterygoid,  digastric,  and  so  on ; 
but  they  are  too  small  to  be  of  much  consequence. 

The  Submental  branch  arises,  then,  on  a  level  with  the  base 
of  the  lower  jaw ;  it  advances  forwards  under  the  origin  of  the 
mylo-hyoides,  and  above  the  anterior  belly  of  the  digastricus. 
It  sends  several  ramuscles  to  these  muscles,  some  of  which 
anastomose  with  the  ranine  artery ;  behind  the  symphysis  of  the 


202  CIRCULATORY  SYSTEM. 

jaw  it  anastomoses  with  its  fellow,  it  then  mounts  over  the  chin, 
to  which  and  to  the  lower  lip  it  is  distributed,  anastomosing 
there  with  the  inferior  coronary  artery  of  the  mouth,  and  with 
the  inferior  maxillary  which  comes  out  from  the  anterior  men- 
tal foramen  in  the  lower  jaw. 

When  the  fascial  artery  has  got  upon  the  face,  it  sends  back- 
wards a  small  branch  to  the  lower  part  of  the  masseter  muscle. 
Somewhat  above  this  it  sends  forwards  a  branch  called  the  In- 
ferior Labial,  which  is  distributed  upon  the  middle  of  the  chin. 
When  it  gets  on  a  level  with  the  corner  of  the  mouth,  but  some- 
times lower  down,  it  sends  forward,  under  the  depressor  anguli 
oris,  the  Inferior  Coronary  Artery,  to  the  lower  lip,  which  fre- 
quently supplies  the  place  of  the  inferior  labial  entirely;  but  when 
the  latter  is  large,  the  •  coronary  is  small  in  proportion :  a  Tew 
lines  higher  up  the  fascial  sends  forward  a  third  branch,  the 
Superior  Coronary,  which  goes  to  the  upper  lip.  These  coro- 
nary arteries  are  very  tortuous,  and  are  distributed  by  many 
branches  in  the  substance  of  the  lips :  by  anastomosing  with 
their  congeners  of  the  other  side,  they  surround  the  mouth  com- 
pletely. The  superior  coronary  artery,  as  it  passes  under  the 
nose,  sends  upwards  one  or  more  small  branches  to  the  integu- 
ments of  its  orifice  and  septum.' 

After  this,  the  facial  artery,  in  ascending  towards  the  internal 
canthus  of  the  eye,  sends  a  branch  to  the  ala  nasi,  and  another 
to  anastomose  with  the  infra-orbitar  artery.  It,  finally,  termi- 
nates at  the  internal  canthus  of  the  eye  by  anastomosing  with 
the  branches  of  the  ophthalmic,  which  come  out  there  upon  the 
side  of  the  root  of  the  nose.  Several  ramuscles,  which  are  too 
small  to  merit  special  description,  are  given  by  the  fascial  to 
the  integuments  and  muscles  of  the  face,  and  to  the  lower 
eyelid. 

The  Inferior  Pharyngeal  Artery  (Art.  Pharyngea  Inferior,  as- 
cendens)  is  one  of  the  smallest  of  the  original  branches  of  the  ex- 
ternal carotid,  and  generally  arises  opposite  to  the  lingual ;  but 
there  is  much  variety  in  the  latter  respect,  it  being  sometimes 
higher  up  or  lower  down,  and  not  unfrequently  a  branch  of  one 
of  the  other  arteries,  instead  of  being  an  original  trunk.  It 
ascends  on  the  side  of  the  pharynx,  between  the  external  and 


CAROTIDS,  AND  THEIR  BRANCHES.  203 

the  internal  carotid,  and  is  covered  by  the  stylo-pharyngeus 
muscle.  It  is  principally  distributed  on  the  constrictor  muscles 
of  the  pharynx,  and  upon  their  lining  membrane.  But  one  of  its 
branches,  called  the  Posterior  Meningeal  Artery,  ascends  through 
the  posterior  foramen  lacerum  of  the  cranium,  between  the  jugu- 
lar vein  and  the  pneumo-gastric  nerve,  and  is  distributed  on  the 
contiguous  dura  mater. 

The  Occipital  Artery  (Arteria  Occipitalis)  is  a  very  considera- 
ble trunk,  which  comes  from  the  external  carotid,  generally  op- 
posite to  the  facial,  and  is  spent  upon  the  integuments,  on  the 
back  part  of  the  head. 

At  its  root,  it  is  deeply  situated  in  the  side  of  the  neck,  below 
the  parotid  gland,  and  has  the  internal  jugular  vein  and  the  par 
vagum  on  its  inside.  It  goes  obliquely  backwards,  in  ascending 
along  the  posterior  belly  of  the  digastricus  between  the  trans- 
verse process  of  the  atlas  and  the  mastoid  portion  of  the  tempo- 
ral bone,  being  covered  by  the  several  muscles  which  are  in- 
serted into  the  latter,  as  the  sterno-mastoid,  the  splenius,  and  the 
trachelo-mastoid.  It  is  covered,  for  some  distance,  by  the  in- 
sertion of  the  splenius  capitis,  and  becomes  at  length  superficial 
at  the  posterior  margin  of  this  muscle.  The  occipital  artery  is 
distributed  as  follows : 

Shortly  after  its  origin,  it  sends  branches  to  the  digastric 
muscle  behind,  to  the  upper  part  of  the  sterno-mastoid  and  to 
the  lymphatic  glands  of  the  upper  part  of  the  neck.  While  en- 
closed by  the  muscles  on  the  back  of  the  neck,  it  also  sends 
branches  to  them,  and  anastomoses  thereby  with  the  vertebral 
artery;  occasionally,  one  of  these  branches  is  of  considerable 
magnitude,  and  has  been  found  descending  very  low  on  the  back, 
between  the  splenius  and  the  complexus  muscles.  '  It  also  sends 
a  small  branch  to  the  dura  mater,  through  the  mastoid  foramen 
generally,  but  sometimes  through  the  posterior  fprameri  lacerum. 
When  the  stylo-mastoid  artery  is  wanting,  it  also  detaches  a 
branch  through  the  stylo-mastoid  foramen  to  the  internal  parts 
of  the  ear. 

The  occipital  artery,  having  become  superficial  at  the  inter- 
nal margin  of  the  splenius  on  the  occiput,  ascends  on  the  latter 
bone  towards  the  'vertex  in  a  tortuous  manner,  sending  off,  on 


204  CIRCULATORY  SYSTEM. 

each  side,  many  small  ramifications.     It  ends  by  anastomosing 
with  the  posterior  temporal  artery. 

The  Posterior  Auricular  Artery  (Art.  Auricularis  Posterior) 
arises  a  little  above  the  last,  at  the  lower  edge  of  the  parotid 
gland,  from  the  external  carotid,  and  is  one  of  its  smallest 
branches.  It  ascends  backwards  enclosed  by  the  parotid  gland, 
and  afterwards  between  the  meatus  auditorius  externus  and  the 
mastoid  bone :  at  the  latter  place,  it  sends  a  ramification  to  the 
internal  side  of  the  external  ear ;  it  then  ascends  and  is  distri- 
buted, by  small  branches,  on  the  contiguous  integuments  of  the 
side  of  the  head.  While  still  involved  in  the  parotid  gland,  it 
sends  some  small  ramifications  through  the  meatus  externus  to 
its  lining  membrane  and  the  membrana  tympani.  It  then  de- 
taches a  branch  through  the  stylo-mastoid  foramen,  from  which 
the  whole  artery  is  also  named  Stylo-Mastoid ;  but  this  branch, 
as  stated,  sometimes  comes  from  the  occipital.  The  stylo-mas- 
toid passes  along  the  aqueduct  of  Fallopius,  detaching  its  arte- 
riole  to  the  typanum  and  to  the  labyrinth. 

The  External  Carotid  having  given  off  these  trunks,  pene- 
trates vertically  through  the  inner  margin  of  the  parotid  gland, 
and  gives  to  it  several  small  twigs.  When  it  arrives  on  a  line 
with  the  neck  of  the  lower  jaw,  it  divides  into  two  large  trunks; 
one  of  them,  the  Internal  Maxillary,  goes  to  the  parts  within  the 
ramus  of  the  lower  jaw ;  the  other,  being  smaller,  is  the  Tern* 
poral  Artery. 

The  Temporal  Artery  (Arteria  Temporalis)  continues  to  as- 
cend through  the  substance  of  the  parotid,  but  becomes  super- 
ficial in  front  of  the  meatus  externus,  in  mounting  over  the  root 
of  the  zygoma;  it  is  then  distributed  to  the  integuments  on  the 
side  of  the  head. 

It  frequently  sends  off  one  or  two  ramifications,  of  but  little 
volume,  to  the  masseter  muscle.  Just  above  its  root,  and  while 
surrounded  by  the  parotid,  a  branch  of  some  importance,  the 
Transverse  Facial,  (Transfer sails  Faciei,)  leaves  it,  and  crosses, 
horizontally,  the  masseter  muscle,  just  below  the  parotid  duct, 
sometimes  above  it.  This  branch  is  distributed  to  the  adjacent 
integuments  and  muscles,  and  terminates  in  front  by  anasto- 
mosing with  the  facial  and  the  infra-orbitar  artery. 


CAROTIDS,  AND  THEIR  BRANCHES.  205 

A  little  below  the  zygoma,  the  Middle  Temporal  Artery  (Art. 
Temp.  Media)  comes  off  from  the  Temporal,  and,  ascending  with 
the  parent  trunk,  perforates  the  temporal  fascia  at  the  upper 
margin  of  the  zygoma,  and  is  distributed  to  the  temporal  muscle 
by  many  ramifications,  which  anastomose  with  the  deep-seated 
temporal  arteries.  After  this,  some  small  twigs,  called  Auri- 
cular, go  to  the  external  ear  from  the  trunk  of  the  temporal 
artery.  , 

The  temporal  artery,  having  ascended  for  an  inch  or  so  be- 
tween the  aponeurosis  of  the  temporal  muscle  and  the  skin,  it  di- 
vides into  an  Anterior  and  a  Posterior  Branch.  The  former  as- 
cends towards  the  side  of  the  os  frontis,  and  is  distributed  in 
ramuscles  to  the  orbicularis  palpebrarum,  the  belly  of  the  occi- 
pito-frontalis,  and  the  integuments  of  the  front  of  the  cranium, 
anastomosing  with  the .  frontal  artery  and  the  temporal  of  the 
other  side.  The  posterior  branch  is  distributed  on  the  integu- 
ments of  the  middle  of  the  side  of  the  cranium,  anastomosing 
with  the  anterior  branch,  with  its  fellow  of  the  other  side,  and 
with  the  occipital  artery. 

The  Internal  Maxillary  Artery  (Jlrteria  Maxillaris  Inter- 
no]  winds  around  the  neck  of  the  lower  jaw,  and,  passing  be- 
tween the  pterygoid  muscles,  proceeds  in  a  tortuous  manner 
to  the  deepest  points  of  the  zygomatic  fossa.  The  first  part  of 
its  course  is  horizontally  inwards;  it  then  ascends  in  front  of 
the  pterygoideus  externus  to  the  bottom  of  the  temporal  bone, 
or  the  spinous  process  of  the  sphenoidal;  it  then  passes  for- 
wards, within  the  temporal  muscle,  to  the  upper  part  of  the 
pterygo-maxillary  fossa. 

It  sends  off  several  branches,  and  commonly  in  the  following 
order: — 

1.  The  Arteria  Tympanica,  to  the  tympanum,  through  the 
glenoid  fissure. 

2.  The  Arteria  Meningea  Parva,  to  the  dura  mater,  through 
the  foramen  ovale.     It  is  most  frequently  a  branch  of  the  next. 

3.  The  Arteria  Meningea  Magna,  or  Media,  to  the  dura  ma- 
VOL.  II.—  27 


206  CIRCULATORY  SYSTEM. 

ter,  through  the  foramen  spinale.  This  branch  having  entered 
the  cranium,  is  distributed  upon  the  dura  mater  in  the  manner 
marked  off  by  the  furrows  upon  the  internal  face  of  the  tempo- 
ral, the  parietal,  and  the  frontal  bones.  One  of  its  branches  en- 
ters the  aqueduct  of  Fallopius,  through  the  Vidian  Foramen, 
and  is  distributed  upon  the  internal  parts  of  the  organ  of  hear- 
ing, anastomosing  with  the  stylo-mastoid  artery. 

4.  The  Arteria  Maxillaris,  or  Dentalis  Inferior,  descends 
along  the  internal  face  of  the  ramus  of  the  lower  jaw,  and 
having  sent  off  some  ramifications  of  small  size  to  the  contigu- 
ous muscles  and  the  lining  membrane  of  the  mouth,  it  enters 
the  posterior  mental  foramen  with  the  inferior  dental  nerve. 
Going  along  the  canal  in  the  substance  of  the  lower  jaw,  it  de- 
taches successively  from  its  superior  margin  ramifications  to 
the  teeth.  At  the  anterior  mental  foramen  a  trunk  is  sent  for- 
ward as  far  as  the  symphysis,  which  supplies  in  its  course  the 
canine  and  incisor  teeth;  the  remainder  of  the  inferior  maxilla- 
ry artery  comes  out  at  the  foramen,  and  supplies  the  chin,  anas- 
tomosing with  the  facial  artery. 

•5.  The  Arteriae  Temporales  Profundae  are  two  in  number. 
The  first  of  them,  called  Posterior,  arises  next  to  the  inferior 
maxillary.  It  is  concealed  between  the  external  pterygoid  and 
the  temporal  muscle  for  some  distance;  it  then'  ascends  in  the 
posterior  part  of  the  temporal  fossa,  beneath  the  temporal  mus- 
cle, and  is  minutely  distributed  upon  it.  The  anterior  deep 
temporal  artery  is  separated  from  the  posterior,  in  its  origin 
from  the  internal  maxillary,  by  the  pterygoid  and  the  buccal 
arteries.  It  arises  near  the  pterygo-maxillary  fossa;  and,  as- 
cending between  the  temporal  muscle  and  the  fore  part  of  the 
corresponding  fossa,  it  is  minutely  distributed  u^on  the  former, 
anastomosing  with  the  posterior  deep,  and  with  the  middle  tem- 
poral artery. 

6.  The  Arteria3  Pterygoideae  arise  after  the  posterior  deep 
temporal.  They  vary  considerably  in  regard  to  number,  size, 
and  origin,  and  are  distributed  upon  the  pterygoid  muscles,  as 
their  name  implies.  One  of  their  branches,  which  is  sometimes 


CAROTIDS,  AND  THEIR  BRANCHES.  207 

an  independent  trunk  from  the  internal  maxillary,  goes  between 
the  posterior  margin  of  the  temporal  muscle  and  of  the  neck  of 
the  lower  jaw,  in  front  of  the  latter,  to  be  distributed  upon  the 
internal  face  of  the  masseter  muscle. 

7.  The  Arteria  Buccalis,  sometimes  a  branch  of  the  internal 
maxillary,  but  frequently  coming  from  one  of  its  trunks,  either 
the  alveolar  or  the  anterior  temporal,  passes  along  the  external 
face  of  the  upper  jaw,  and  distributes  its  branches  to  the  bucci- 
nator and  zygomatic  muscles,  and  to  the  lining  membrane  of 
the  mouth. 

8.  The  Arteria  Maxillaris  Superior,  or  Alveolaris,  proceeds 
downwards  and  forwards  in  winding  around  the  tuber  of  the 
upper  jaw  bone.     It  first  sends  some  ramifications  through  the 
bone  to  the  roots  of  the  great  and  small  molar  teeth,  and  to  the 
lining  membrane  of  the  maxillary  sinus;  it  then  passes  forwards 
along  the  gums,  near  the  buccinator,  and  gives  ramifications  to 
them  and  to  the  contiguous  muscles. 

9.  The  Arteria  Infra-orbitalis  comes  from  the  internal  maxil- 
lary, at  the  upper  part  of  the  pterygo-maxillary  fossa;  it  sends 
some  inconsiderable  ramifications  to  the  fat  and  the  periosteum 
of  the  orbit,  through  the  spheno-maxillary  fissure.     It  then  en- 
ters the  infra-orbitary  canal,  and  passes  through  it  with  the  in- 
fra-orbitary  nerve.     On  arriving  near  the  anterior  orifice  of  the 
canal,  it  detaches  downwards  a  branch  which  goes  to  the  canine 
and  the  incisor  teeth,  and  to  the  lining  membrane  of  the  an- 
trum.     It  then  gets  to  the  face  below  the  origin  of  the  levator 
labii  superioris  muscle,  and  is  distributed  upon  the  muscles  in 
front  of  the  upper  maxilla,  anastomosing  with  the  facial  and 
with  the  ophthalmic  artery. 

10.  The  Arteria  Palatina  Superior  descends  through  the  pos- 
terior palatine  canal,  and,  having  reached  the  mouth,  leaves 
some  ramifications  with  the  soft  palate:  it  then  advances  be- 
tween the  bones  and  the  lining  membrane  of  the  roof  of  the 
mouth,  and  disperses  itself  in  several  small  twigs;  one  of  which 
passes  through  the  foramen  incisivum  into  the  nostril. 


208  CIRCULATORY  SYSTEM. 

11.  The  Arferia  Pharyngea  Superior  is  sometimes  a  branch 
of  the  last,  and  is  spent  upon  that  portion  of  the  pharynx  bor- 
dering on  the  pterygoid  processes. 

12.  The  Arteria  Spheno-Palatina  is  the  terminating  trunk  of 
the  internal  maxillary;  it  enters  the  nose  through  the  spheno- 
palatine  foramen,  and  divides  into  two  branches,    which    are 
minutely  distributed  over  the  Schneiderian  membrane.     One 
of  them  descends  along  the  septum  narium;  the  other  along  the 
external  margin  of  the  posterior  naris,  and  divides  into  two 
principal  ra muscles,  one  of  which  is  dispersed  along  the  mid- 
dle turbinated,  and  the  other  along  the  inferior  turbinated  bone. 

SECt.  III. OF  THE  SUBCLAVIAN  ARTERY,  AND  ITS 

BRANCHES. 

The  Subclavian  Artery  (Arteria  Subclavia]  of  the  right  side 
having  arisen  from  the  innominata,  and  that  of  the  left  from  the 
aorta,  they  each  go  over  the  first  rib  of  their  respective  sides, 
adhering  closely  to  it,  in  the  bottom  of  the  interval  between  the 
scalenus  anticus  and  medius  muscles.  The  right  subclavian  is 
much  shorter,  and  more  superficial  than  the  left,  from  its  origin 
to  the  scaleni  muscles.  Near  the  latter  they  are  each  covered 
in  front  by  the  sternal  end  of  the  clavicle,  by  the  sterno-hyoid 
and  thyroid  muscles,  and  by  the  subclavian  vein  of  the  corre- 
sponding side;  behind  they  are  separated  from  the  vertebral  co- 
lumn by  the  longus  colli  muscle;  below  them  is  the  pleura,  the 
left  artery  being  in  contact  with  it  for  its  whole  passage  in  the 
thorax;  and  on  their  internal  side  is  the  primitive  carotid.  The 
subclavian  of  the  right  side  is  crossed  near  the  scalenus  anticus 
by  the  par  vagum ;  the  phrenic  nerve  also  goes  in  front  of  it, 
but  on  the  internal  edge  of  the  scalenus.  The  subclavian  of  the 
left  side  having  a  course  almost  vertical  from  its  origin  to  the 
interval  of  the  scaleni  muscles,  is  nearly  parallel  with,  and  be- 
hind, the  primitive  carotid  of  that  side;  the  phrenic  nerve  has 
the  same  relative  position  with  it  as  on  the  right  side;  but  the 
par  vagum  goes  parallel  with,  and  in  front  of  the  subclavian  ar- 
tery, for  some  distance  along  the  root  of  the  latter. 

At  the  inner  margin  of  the  Scaleni  Muscles  the  Subclavian 


SUBCLAVIAN,  AND  ITS  BRANCHES.  209 

gives  off  a  cluster  of  trunks;  to  wit,  the  Vertebral;  the  Inferior 
Thyroidal;  the  Superior  Intercostal;  the  Internal  Mammary; 
and  the  Cervical  Artery.  They  sometimes  arise  distinctly,  and 
after  the  order  mentioned;  but  there  is  too  great  a  diversity  in 
subjects  to  establish  any  rule  on  these  points. 

1.  The  Vertebral  Artery  (JLrleria  Vertebralis)  is  the  most 
voluminous  of  the  branches  of  the  Subclavian.     Immediately  af- 
ter its  origin  it  ascends  on  the  side  of  the  spine,  and  enters  the 
canal  of  the  transverse  processes  of  the  neck  at  the  sixth  ver- 
tebra.    Pursuing  this  course,  it  gets  into  the  cavity  of  the  cra- 
nium through  the  foramen  magnum  occipitis,  and  is  distributed 
to  the  brain  in  the  manner  mentioned  in  the  description  of  that 
organ. 

While  in  the  canal  of  the  transverse  processes,  it  sends  off 
several  branches  to  the  heads  of  the  contiguous  muscles,  and  to 
the  medulla  spinalis  of  the  neck. 

2.  The  Inferior  Thyroid  Artery  (Jlrteria   Thyroidea  Infe- 
rior} arises  from  the  upper  face  of  the  subclavian,  and  goes  to  the 
thyroid  gland.     It  ascends  at  first  on  the  internal  margin  of  the 
scalenus  medius  muscle,  and  then  turns  suddenly  inwards  be- 
tween the  vertebra  and  the  great  vessels  of  the  neck. 

In  this  course  several  unimportant  twigs  are  sent  from  it  to 
the  contiguous  parts.  Near  its  root  it  detaches  the  Anterior, 
or  the  Ascending  Cervical  Artery,  which  going  up  the  neck  is 
spent  upon^the  heads  of  the  muscles  arising  from  the  transverse 
processes,  as  the  scaleni,  the  longus  colll,  and  so  on.  The  infe- 
rior thyroidal  then  gets  to  the  thyroid  glan<$^and  is  very  mi- 
nutely distributed  to  it,  anastomosing  with  tiie  other  arteries 
which  supply  the  same  organ. 

\ 

3.  The  Superior  Intercostal  Artery,  (Jlrteria  Intercostalis 

Superior,)  arising  from  the  under  surface  of  the  subclavianjpp- 
posite  the  inferior  thyroid,  descends  across  the  neck  of  the  first 
rib,  and  divides  into  two  branches,  which  supply  the  two  upper 
intercostal  spaces:  each  of  them  also  sends  backwards  near-tfee 
vertebra  a  small  trunk  to  the  muscles  of  the  back. 


210  CIRCULATORY  SYSTEM. 

4.  The  Internal  Mammary  Artery  (Jirteria  Mammctria  In- 
terna,  Thoracica)  descends  at  first  along  the  internal  margin  of 
the  scalenus  anticus;  having  then  got  fairly  into  the  cavity  of 
the  thorax,  it  continues  to  descend  across  the  posterior  face  of 
the  costal  cartilages,  parallel  with,  and  about  nine  lines  from, 
the  outer  edge  of  the  sternum,  between  the  triangularis  sterni 
and.  the  intercostal  muscles. 

In  this  course,  besides  some  distinct  twigs  to  the  anterior  me- 
diastinum, it  sends  a  branch  (Phrenica  Superior)  which  accom- 
panying the  phrenic  nerve  between  the  pleura  and  the  pericar- 
'dium,  reaches  finally  the  diaphragm,  and  is  spent  upon  it.  At 
each  intercostal  space  which  it  crosses,  the  internal  mammary 
sends  outwards  a  branch^  which  is  spent  upon  the  fore  part  of 
the  intercostal  muscles,  and  anastomoses  with  the  correspond- 
ing intercostal  artery:  other  branches  also  leave  it  at  each  space, 
which  getting  forwards  near  the  sternum,  are  distributed  upon 
the  pectoralis  major,  and  upon  the  contiguous  muscles.  The 
last  of  these  branches,  according  to  M.  H.  Cloquet,  goes  trans- 
versely over  the  ensiform  cartilage,  and,  having  anastomosed 
with  its  fellow,  descends  between  the  peritoneum  and  the  linea 
alba  to  the  suspensory  ligament  of  the  liver. 

On  a  line  generally  with  the  anterior  extremity  of  the  fifth 
rib,  the  internal  mammary  divides  into  two  principal  branches; 
the  most  exterior  of  which,  descending  along  the  cartilaginous 
margin  of  the  thorax,  is  distributed  in  small  twigs  to  the  origin 
there  of  the  diaphragm  and  of  the  transverse  muscle  of  the  ab- 
domen. The  internal  branch  reaches  the  posterior  face  of  the 
rectus  abdominis  muscle,  and  is  dispersed  upon  it:  some  of  its 
branches  go  as  low  as  the  umbilicus,  to  anastomose  there  with 
the  epigastric  artery. 

5;  The  posterior  Cervical  Artery  (*Arteria  Cervicalis  Pos- 
terior, Tr(tnsversa)  is  of  a  very  unsettled  origin,  but  comes 
most  frequently  either  from  the  subclavian  itself,  or  from  the 
inferior  thyroid.  It  is  but  small  in  some  subjects,  owing  to 
its  place  being  supplied  by  branches  from  the  adjoining  arteries. 

It  crosses  horizontally  the  root  of  the  neck  on  the  outer  face 
of  the  scaleni  muscles  above  the  subclavian  artery.  It  gets 


SUBCL AVIAN,  AND  ITS  BRANCHES.  211 

under  the  anterior  margin  of  the  trapezius,  and  is  there  divided 
into  two  principal  branches;  the  ascending  one  is  spent  upon 
the  trapezius  and  the  levator  scapulae;  the  other  descends  along 
the  base  of  the  scapula,  and  is  spent  in  ramifications  upon  the 
rhomboidei  and  the  serratus  magnus  muscles.  Several  branches 
of  minor  size  and  importance  are  sent  off  from  the  posterior 
cervical  artery  to  the  muscles  on  the  back  of  the  neck  -and 
thorax. 

The  Subclavian  Artery  having  sent  off  the  preceding  branches, 
then  escapes  from  the  thorax  between  the  scaleni  muscles,  and 
gets  to  the  arm-pit  between  the  first  rib  and  the  subclavius 
muscle.  The  trunk  of  it  is  then  continued  downwards  through 
the  axilla,  and  at  the  inner  side  of  the  arm  to  the  elbow  joint. 

From  the  scaleni  muscles  to  the  elbow  its  relative  position  is 
as  follows:  When  it  first  appears  between  the  scaleni,  it  is 
bounded  above  and  behind  by  the  collected  fasciculi  of  the  ax- 
illary plexus  of  nerves.  In  front  it  is  separated  from  the  sub- 
clavian  vein  by  the  insertion  of  the  scalenus  anticus.  It  is 
placed  at  the  bottom  of  the  depression  between  the  sterno-ma- 
stoideus  and  the  trapezius,  _being  covered  by  the  skin,  the  pla- 
tysma  myodes,  and  some  loose  cellular  substance  below  the 
latter.  It  then  descends  between  the  first  rib  and  the  subcla- 
vius; escaping  from  below  the  latter,  it  is  covered  in  front  by 
the  outer  margin  of  the  pectoralis  major  until  it  reaches  the 
lower  part  of  the  axilla;  and  in  this  course  it  has  the  following 
relation  to  other  parts:  it  passes  under  the  shoulder  joint,  then 
under  the  insertion  of  the  pectoralis  minor,  then  along  the  in- 
ternal face  of  the  coraco-brachialis  muscle;  it  has  the  axillary 
vein  in  front  of  it,  and  the  axillary  nerves  plaited  around  it  as 
far  down  as  the  coracoid  process,  when  they  begin  to  disperse. 
This  artery  in  emerging  from  the  axilla  is  placed  upon  the  an- 
terior face  of  the  insertion  of  the  latissimus  dorsi:  it  then  runs 
out  the  length  of  the  coraco-brachialis,  and  is  afterwards 
conducted  along  the  inner  margin  of  the  biceps  flexor  cubiti 
and  its  tendinous  termination:  it  lies  upon  the  anterior  face 
of  the  brachialis  internus;  and  goes  beneath  the  aponeurosis  at 
the  bend  of  the  arm,  coming  from  the  tendon  of  the  biceps. 
In  the  arm  it  is  concealed  only  by  the  integuments  and  fascia, 


212  CIRCULATORY  SYSTEM. 

and  is  bordered  internally  by  the  brachial  vein  and  the  median 
nerve. 

This  great  trunk  of  the  upper  extremity  loses  the  name  of 
subclavian,  to  be  called  Axillary  Artery,  (*3rt.  •flxillaris,)  from 
the  subclavian  muscle  to  the  lower  margin  of  the  arm-pit:  and 
from  the  latter  place  to  the  elbow  joint,  it  is  named  Brachial 
Artery,  (Jlrt.  Brachialis.')  It  sends  oft'  many  interesting 
branches  to  the  thorax,  to  the  shoulder,  and  to  the  arm;  and, 
finally,  terminates  a  little  below  or  at  the  elbow  joint  by  bifur- 
cating. 

Of  the  Branches  of  the  Axillary  Jlrtery. 

1.  The  Superior  Scapular  Artery  (*ff.rt.  Dorsalis  Superior 
Scapula?)  varies  considerably  in  its  origin.     Sometimes  it  is  a 
branch  of  the  subclavian,  sometimes  of  the  inferior  thyroid,  and 
it  frequently  comes  from  the  upper  part  of  the  axillary;  so  that 
it  cannot  be_referred,  with  strict  propriety,  to  any  determined 
origin.     When  it  comes  from  the  axillary,  it  is  very  tortuous, 
and  has  to  ascend  to  its  destination,  which  removes  it  entirely 
from  any  interference  with  the  course  of  the  subclavian  over 
the  first  rib,  and  over  the  upper  head  of  the  serratus  magnus 
muscle.     But  in  the  other  cases,  it  goes  transversely  backwards 
and  outwards,  somewhat  below  the  posterior  cervical,  and  along 
the  posterior  inferior  margin  of  the  clavicle,  being  covered  by 
the  sterno-mastoideus,  the  platysma  myodes,  and  the  trapezius; 
consequently,  it  is  just  in   the  way   of  the  incisions  which  are 
made  for 'reaching  the  subclavian  artery,  from  above  the  clar 
vicle. 

It  reaches  the  superior  costa  of  the  scapula  near  the  root  of 
the  coracoid  process,  and  passing  through  the  notch  there,  is 
distributed,  by  one  large  branch,  upon  the  supra-spinatus  muscle; 
and  by  another,  which  goes  across  the  anterior  margin  of  the 
spine  of  the  scapula,  to  the  infra-spinatus  muscle.  In  its  course, 
it  sends  oft*  several  small  ramifications  to  contiguous  parts. 

2.  The  External  Mammary  Arteries  (Art.  Mammarm  sen  Tho- 

Extern®')  arise  from  the  axillary,  between  the  subclavius 


SUBCLAVIAN,  AND  ITS  BRANCHES.  213 

and  the  pectoralis  minor  muscle.  They  are  four  principal 
trunks,  which  go  uniformly  to  certain  parts,  but  vary  considera- 
bly in  their  origin ;  for  sometimes  the  latter  is  distinct  in  the 
case  of  each  artery,  but  frequently  otherwise.  Their  distribu- 
tion is  as  follows: 

a.  The  Thoracica  Superior  is  distributed  to  the  upper  part  of 
the  pectoralis  major  muscle,  and  to  the  pectoralis  minor.     Some 
of  its  branches  reach  the  mamma  in  the  female,  and  anastomose 
with  the  internal  mammary  and  with  the  intercostals. 

b.  The  Thoracica  Longa  descends  along  the  posterior  face  of 
the  pectoralis  major,  between  it  and  the  serratus  magnus.     It 
gives  many  branches  to  the  lower  part  of  the  pectoralis  major, 
to  the  integuments,  and,  in  the  female,  to  the  mamma ;  anasto- 
mosing likewise  with  the  internal  mammary  and  with  the  inter- 
costals. 

c.  The  Thoracica  Acromialis,  immediately  after  its  origin, 
makes  for  the  fissure  between  the  deltoid  and  the  great  pectoral 
muscle,  and  divides  there  into  an  ascending  and  a  descending 
branch.     The  former  reaches  the  clavicle,  and  is  partly  distri- 
buted superficially  along  it,  partly  to  the  contiguous  muscles, 
and  to  the  shoulder  articulation.     The  other  branch  follows  the 
cephalic  vein  along  the  interstice  between  the  deltoides  and  pec- 
toralis major,  and  is,  finally,  distributed  to  these  muscles  and  to 
the  integuments. 

d.  The  Thoracica  Axillaris  is  irregular,  both  in  regard  to  the 
number  of  its  branches  and  to  their  origin.     Instead  of  a  distinct 
origin   by  one   or  more  trunks  from  the   axillary  artery,  the 
branches  belonging  to  the  name  of  thoracica  axillaris,  are  some- 
times derived  from  the  other  thoracic  arteries.     They  are  ge- 
nerally distributed  only  to  the  fat  and  the  lymphatic  glands  in 
the  axilla.     They  occasionally  exist  primitively  as  a  large  trunk, 
which  runs  on  the  scapular  face  of  the  serratus  magnus  the 
whole  length  of  the  scapula,  and  is  distributed  to  the  adjacent 
muscles,  and  to  the  fat  and  glands  of  the  axilla. 

3.  The   Scapular  Artery  (Arteria  Scapularis  communis,  Sub- 
scapularis]  arises  from  the  axillary  below  the  shoulder  joint,  at 
or  near  the  anteriojr  margin  of  the  subscapularis  muscle.   Giving 
VOL.  II.— 28 


214  CIRCULATORY  SYSTEM. 

off  some  inconsiderable  branches  to  the  lymphatic  glands  of  the 
arm-pit,  it  descends  along  the  anterior  margin  of  the  subscapir 
laris,  and  is  distributed  to  it,  to  the  latissimus  dorsi,  and  to  the 
teres  major  and  minor  muscles. 

A  little  below  the  neck  of  the  scapula,  it  detaches  a  large 
trunk,  the  Dorsalis  Inferior  Scapulae,  which,  winding  around  the 
inferior  costa  of  the  bone  over  the  anterior  margin  of  the  sub- 
scapularis  and  the  teres  minor,  reaches  the  fossa  infra-spinatar 
This  trunk  then  divides  into  two  branches :  one  of  which  is  dis- 
tributed superficially  between  the  aponeurosis  and  the  infra-spi- 
natus,  and  the  other  more  deeply  near  the  dorsum  of  the  bone: 
one  of  the  ramuscles  of  the  latter  ascends  beneath  the  neck  of 
the  .Acromion  to  anastomose  with  the  Dorsalis  Superior  Sca- 
pulas. 

4.  The  Anterior  Circumflex  Artery  (Art.  Circumflexa  Anterior? 
Articularis  Anterior)  is  about  the  size  of  a  crow  quill,  and  arises 
from  the  axillary  just  above  the  tendon  of  the  teres  major  and 
of  the  latissimus  dorsi.  It  adheres  closely  to,  and  surrounds  the 
front  of  the  neck  of  the  os  humeri,  passing  between  it,  the  cora- 
co-brachialis,  and  the  short  head  of  the  biceps.  It  then  divides 
into  several  branches,  some  of  which  go  to  the  deltoides,  and 
anastomose  therewith  the  posterior  circumflex;  others  go  imme- 
diately to  the  articulation,  and  either  terminate  on  it  or  ascend 
to  the  muscles  on  the  dorsum  of  the  scapula,  where  they  anasto- 
mose with  the  scapular  arteries. 

The  Posterior  Circumflex  Artery  (Art,  Circumflexa  Posterior]  is 
much  larger  than  the  last,  and  arises  from  the  axillary  somewhat 
below  it.  It  surrounds  the  posterior  face  of  the  neck  of  the  os  hu- 
meri, passing  between  it  and  the  long  head  of  the  triceps  muscle, 
below  the  insertion  of  the  teres  minor.  Many  of  its  ramifica- 
tions go  to  the  capsular  ligament  of  the  articulation  and  to  the 
muscles  adhering  to  it.  But  this  artery  is  principally  intended 
for  the  deltoid  muscle,  to  the  internal  face  of  which  the  most  of 
its  branches  go.  It  anastomoses  with  the  anterior  circumflex, 
and  with  the  scapular  arteries. 

In  some  cases,  the  posterior  circumflex  arises  from  the  axil- 
lary below,  instead  of  above  the  tendinous  insertion  of  the  latis- 
simus dorsi:  when  this  happens,  it  commonly  gives  off  the  arte- 


SUBCLAVIAN,  AND  ITS  BRANCHES,  215 

Tia  profunda  major  of  the  arm,  and  afterwards  ascends  on  the 
posterior  face  of  the  tendon  to  its  appropriate  destination. 


Of  the  Branches  of  the  Brachial  Artery. 

1.  The   Profound  Artery  (Arleria  Profunda   Major 4  Humeri, 
Spiralis)  arises  from  the  brachial,  a  little  below  the  tendinous 
insertion  of  the  latissimus  dorsi;  and  having  passed  downwards, 
for  a  short  distance,  it  enters  the  interstice  between  the  first  and 
the  third  head  of  the  triceps  muscle,  and  winds  spirally  down- 
wards around  the  ps  humeri  in  company  with  the  radial  nerve. 
On  the  outer  side  of  the  arm,  it  becomes  superficial  between  the 
margins  of  the  triceps  and  of  the  brachialis  internus,  and  then 
directs  its  course  between  the  latter  and  the  supinator  longus  to 
the  external  condyle. 

In  this  course,  the  artery  sends  several  branches  to  the  triceps 
muscle,  to  which,  indeed,  it  is  principally  destined.  Near  the 
external  condyle,  it  supplies  the  brachialis  internus  and  the  heads 
of  the  extensor  muscles  of  the  fore  arm,  and  anastomoses  with 
the  recurrent  branch  of  the  radial  artery. 

2.  The  Small  Profound  Artery  (Art.  Profunda  Minor]  comes 
from  the  brachial,  two  or  three  inches  below  the  profunda  ma- 
jor, but  frequently  it  is  only  a  branch  of  the  latter,  and  is  gene- 
rally much  smaller.     It  is  distributed  superficially  on  the  internal 
face  of  the  triceps  at  its  lower  part,  and  has  its  terminating 
branches  reaching  as  far  as  the  internal  condyle. 

3.  The  Nutritious  Artery  (Art.  Nutritia)  is  the  next  in  order 
from  the  brachial;  and  arises  from  it  near  the  medullary  fora- 
men of  the  os  humeri,  through  which  it  penetrates,  and  is  distri- 
buted to  the  lining  membrane  of  the  bone.     It  is  not  larger  than 
a  knitting  needle. 

4.  The  Anastomotic  Artery  (Arteria  Anaslomotica)  arises  from 
the  brachial  below  the  last,  and  is  larger  than  it.     It  lies  upon 
the  lower  internal  part  of  the  brachialis  internus  muscle,  and 
crosses  the  ridge  leading  to  the  internal  condyle  in  order  to 


216  CIRCULATORY  SYSTEM. 

reach  the  depression  between  the  latter    and  the  olecranon, 
where  it  anastomoses  with  the  ulnar  recurrent  artery. 

The  preceding  is  a  common  arrangement  of  the  branches 
proceeding  from  the  brachial  artery,  yet  deviations  from  it  are 
continually  met  with,  in  a  deficiency  or  in  a  redundancy  of  these 
collateral  trunks,  and  in  their  mode  of  origin.  An  account  of 
all  the  varieties  which  are  observed  here  would  be  almost  end- 
less, as  every  subject  has  some  peculiarity.  Several  small  ar- 
teries are  also  sent  from  the  brachial  to  the  coraco-brachialis, 
the  biceps,  the  brachialis  internus,  and  to  the  triceps  muscles. 
They,  for  the  most  part,  are,  simply,  muscular  branches,  which 
are  too  small  and  irregular  to  deserve  specifying. 

A  division  of  the  brachial  artery  into  two  trunks,  the  Radial 
and  the  Ulnar,  will  be  found  in  a  majority  of  subjects  in  front 
of  the  brachialis  internus  muscle  on  a  line  with  the  elbow  joint : 
sometimes  it  occurs  nearer  the  root  of  the  coronoid  process, 
It  is,  however,  by  no  means  rare  to  see  this  bifurcation  much 
above  the  elbow.  Examples  of  it  have  been  witnessed  at  every 
point  between  the  latter  and  the  arm-pit ;  in  such  cases,  the 
course  of  the  radial  artery  down  the  fore  arm  is  generally  much 
more  superficial  than  usual,  as  it  is  placed  immediately  below* 
the  skin. 

Of  the  Radial  Artery. 

The  Radial  Artery  (Arteria  Radialis)  is  smaller  than  the  ulnar, 
and  extends  from  the  elbow  to  the  hand.  In  the  upper  half  of 
the  fore  arm  it  is  placed  at  the  bottom  of  the  fissure  between 
the  supinator  radii  longus  and  the  pronator  teres  muscle.  Having 
crossed  the  insertion  of  the  latter,  it  runs  in  front  of  the  radius 
between  the  tendon  of  the  supinator  and  of  the  flexor  carpi  ra- 
dialis.  Below  the  styloid  process  of  the  radius  it  runs  between 
the  outer  end  of  the  carpus  and  the  extensor  muscles  of  the 
thumb ;  it  then  penetrates  to  the  palm  of  the  hand  between  the 
root  of  the  metacarpal  bone  of  the  thumb  and  of  the  fore  finger, 
above  the  abductor  indicis  muscle. 

The  following  branches  are  sent  from  the  Radial  Artery. 


SUBCLAVIAN,  AND  ITS  BRANCHES.  217 

1.  The  Recurrens  Radialis  arises  at  the  neck  of  the  radius. 
It  winds,  externally,  around  the  joint  between  the  external  con- 
dyle  and  the  muscles  coming  from  it,  and  anastomoses  with  the 
spiralis  of  the  humeral  artery,  being  distributed  in  many  colla- 
teral branches,  to  the  joint  and  to  the  contiguous  muscles. 

2.  Several  small  and  irregular  muscular  branches  arise  from 
the  radial  artery,  in  its  progress  to  the  wrist :  they  have  no  ap- 
propriate names. 

3.  The  Superficial  Volae  arises  from  the  radial  about  the  in- 
ferior margin  of  the  pronator  quadratus  muscle.     It  passes  su- 
perficially over  the  process  of  the  trapezium  to  the  muscles  of 
the  ball  of  the  thumb,  and  one  of  its  terminating  branches  joins 
the  arc  us  sublimis.     Sometimes  the  superficial  volas  is  the  prin- 
cipal branch  of  the  radial. 

4.  The  Dorsalis  Carpi  arises  from  the  radial  at  the  carpus, 
runs  across  the  back  of  the  latter  below  the  extensor  tendons, 
and  detaches  the  posterior  interosseous  arteries  of  the  back  of 
the  hand.     They  anastomose  with  branches  from  the  ulnar  and 
interosseous  arteries  of  the  fore  arm. 

5.  The  Magna  Pollicis,  a  terminating  branch  of  the  radial, 
comes  from  it  in  the  palm  of  the  hand  just  at  the  root  of  the  me- 
tacarpal  bone  of  the  thumb.     It  runs  beneath  the  abductor  indi- 
cis,  and  at  the  head  of  the  metacarpal  bone  divides  into  two 
branches  which  run  along  the  sides  of  the  thumb  to  its  extremity, 
where  they  anastomose  and  terminate. 

6.  The  Radialis  Indicis,  arising  at  the  same  place  with  the 
latter,  runs  along  the  metacarpal  bone  of  the  fore  finger,  and 
along  the  radial  side  of  the  same  finger  to  its  extremity. 

7.  The  Palmaris  Profunda  is  the  third  terminating  branch  of 
the  radial  artery.     It  arises  near  the  same  place  with  the  two 
last,  crosses  the  hand  between  the  metacarpal  bones  and  the 
flexor  tendons;  thus  forming  the  Arcus  Profundus,  from  which 
branches  proceed  to  the  interossei  muscles,  and  which  ends  on 


218  CIRCULATORY  SYSTEM. 

the  ulnar  side  of  the  palm  of  the  hand  by  a  branch  to  the  Arcus 
Superficialis. 


Of  the  Ulnar  Artery. 

The  Ulnar  Artery,  (Arteria  Ulnaris,)  one  of  the  forks  of  the 
brachial  at  the  elbow,  passes  more  in  a  line  with  it  than  the  ra- 
dial artery  does.  It  goes,  immediately  after  its  origin,  under  se- 
veral of  the  muscles  of  the  internal  condyle,  to  wit :  the  pronator 
teres,  flexor  radialis,  flexor  sublimis,  and  palmaris  longus,  and 
between  the  flexor  sublimis  and  profundus  digitorum,  being  deep- 
ly seated ;  getting  from  beneath  the  flexor  sublimis,  it  afterwards 
runs  parallel  with  the  ulna,  or  nearly  so,  lying  on  the  flexor  pro- 
fund  as  between  the  flexor  ulnaris  and  the  ulnar  margin  of  the 
flexor  sublimis,  and  concealed  two-thirds  of  the  way  down  the 
fore  arm  by  the  overlapping  of  these  muscles.  At  the  thin  part 
of  the  fore  arm,  commonly  called  the  wrist,  it  is  superficial,  and 
may  be  felt  pulsating  in  the  living  body  at  the  radial  margin  of 
the  tendon  of  the  flexor  ulnaris. 

The  ulnar  artery,  at  the  carpus,  takes  a  very  different  course 
from  the  radial,  for  it  passes  over  the  anterior  annular  ligament 
of  the  carpus  just  at  the  radial  side  of  the  os  pisiforme,  to  which 
it  is  held  by  a  small  ligamentous  noose ;  it  then  proceeds  to  the 
palm  of  the  hand.  Between  the  aponeurosis  palmaris  and  the 
flexor  tendons  it  forms  that  curve  from  the  ulnar  to  the  radial 
side  of  the  hand  called  the  Arcus  Sublimis.  This  curve  com- 
monly begins  a  little  beyond  the  anterior  margin  of  the  annular 
ligament,  and  presenting  its  convexity  forwards,  terminates  about 
the  middle  of  the  ball  of  the  thumb  at  its  inner  margin. 

The  branches  sent  from  the  ulnar  artery  are  as  follow: — 

1.  The  Recurrens  Ulnaris   arises  from  the  ulnar  about  the 
lower  part  of  the  tubercle  of  the  radius,  and,  winding  upwards, 

.  is  distributed  in  small  branches  to  the  muscles  of  the  internal 
condyle.  One  of  its  ramuscles  goes  between  the  internal  con- 
dyle and  the  olecranon  process  to  anastomose  with  the  arteria 
anastomotica  of  the  humeral. 

2.  The  Interossea  arises  from  the  ulnar,  just  below  the  other. 


SUBCLAVIAN,  AND  ITS  BRANCHES.  219 

It  is  a  large  trunk,  and  proceeds  but  a  little  distance  when  it  di- 
vides into  two  principal  branches,  called  anterior  and  posterior 
interosseal  arteries. 

a.  The  Interossea  Anterior  is  much  the  larger;  it  runs  in  con- 
tact with  the  interosseous  ligament  to  the  upper  margin  of  the 
pronator  quadratus,  giving  off  branches  to  the  deep-seated  mus- 
cles of  the  fore  arm  in  its  course.  Under  the  pronator  it  per- 
forates the  interosseous  ligament,  and  distributes  branches  to  the 
back  of  the  carpus  and  of  the  hand,  which  anastomose  with 
branches  of  the  radial  and  posterior  interosseal. 

6.  The  Interossea  Posterior  is  sometimes  a  separate  trunk, 
arising  from  the  ulnar  just  above  the  former.  In  either  case  it 
soon  perforates  the  interosseous  ligament  to  get  to  the  back  of 
the  fore  arm.  Here  it  sends  backwards  a  Recurrent  Branch 
(Recurrens  Interossea)  to  the  back  of  the  elbow,  which  anasto- 
moses with  the  recurrens  ulnaris  and  radialis.  It  then  proceeds 
downwards,  being  deeply  seated  and  distributed  to  the  different 
muscles  on  the  back  of  the  fore  arm.  Some  of  its  branches 
reach  the  wrist,  and  anastomose  with  the  carpal  arteries. 

3.  The  ulnar  artery,  in  its  descent  on  the  fore  arm,  sends  off 
many  small  and  irregular  muscular  branches,  called  by  Pro- 
fessor Chaussier,  Cubito-muscularis:  they  do  not  require  descrip- 
tion. 

4.  The  Dorsalis  Manus  leaves  the  ulnar  at  the  lower  end  of 
the  fore  arm,  and  passes  under  the  tendon  of  the  flexor  ulnaris 
to  the  back  of  the  hand.     It  there  meets  ramuscles  of  the  radial 
and  interosseous,  and  conjointly  they  supply  with  very  small 
branches  the  back  of  the  wrist,  of  the  metacarpus,  and  of  the 
fingers. 

5.  As  the  Arcus  Sublimis  is  about  beginning,  the  ulnar  arte- 
ry sends  superficial  but  small  branches  to  the  integuments  of  the 
palm;  and  a  little  farther  on,  a  considerable  branch,  which  dives 
into  the  bottom  of  the  palm,  through  thef  muscles  of  the  little 
finger,  and  joins  the  ulnar  extremity  of  the  arcus  profundus:  this 
is  the  Cubitalis  Manus  Profunda  of  Haller. 


220  CIRCULATORY  SYSTEM. 

6.  The  Arcus  Sublimis  then  sends  a  hranch  to  the  ulnar  side 
of  the  little  finger.  Afterwards  in  succession  three  digital 
branches  are  sent  off,  which,  arriving  at  the  interstices  between 
the  heads  of  the  metacarpal  bones,  each  divides  into  two 
branches  to  supply  the  sides  of  the  fingers  which  are  opposite 
to  each  other;  one  branch  is  called  Digito-radial,  the  other  Di- 
gito-ulnar,  according  to  the  side  of  the  finger  on  which  the  ar- 
tery may  be  placed. 

The  digital  arteries,  before  they  divide,  receive  each  a  small 
branch  from  the  arcus  profundus.  The  digito-radial,  and  the 
digito-ulnar  arteries,  pass  along  the  sides  of  the  fingers  in  front 
to  their  extremities:  at  the  joints  and  extremities,  anastomoses 
between  the  arteries  of  the  two  sides  of  the  same  finger  fre- 
quently occur. 

The  arcus  sublimis  terminates  on  the  radial  side  of  the  palm 
by  a  branch  which  joins  the  inner  branch  of  the  Arteria  Magna 
Pollicis  of  the  Radial. 

The  most  frequent  distribution  of  the  arteries  of  the  hand  is 
what  has  just  been  described:  anatomists  are,  however,  not  all 
agreed  on  this  point.  It  would  probably  be  more  just  to  say, 
that  this  occurs  more  frequently  than  any  other  single  arrange- 
ment. The  varieties,  in  fact,  are  so  great,  that  before  a  hand  is 
opened,  it  is  not  possible  to  know  in  what  manner  its  arteries 
will  be  distributed.  Sometimes  the  Radial  Artery  furnishes 
one  half  of  the  arcus  sublimis,  and  the  Ulnar  the  other  half. 
On  other  occasions,  the  interosseous  artery  or  the  superficialis 
volae  is  continued  as  a  large  trunk  over  the  ligament  of  the 
wrist,  and  crosses  the  root  of  the  thumb,  to  join  the  arcus  sub- 
limis. 


SECT.   IV. — BRANCHES  OF  THE  DESCENDING  THORACIC 
AORTA. 

The  Aorta,  in  its  course  from  the  lower  part  of  its  curvature 
to  the  crura  of  the  Diaphragm,  gives  off  several  branches  to  the 
viscera  and  to  the  parietes  of  the  thorax. 

The  Bronchial  Arteries  (<flrterias  Bronchiales)  are  the  nu- 


SUBCLAVIAN,  AND  ITS  BRANCHES.  221 

tritious  vessels  of  the  lungs.  There  is  commonly  one  for  each 
lung,  but  sometimes  two  or  more.  The  right  arises  frequently 
from  the  superior  aortic  intercostal  artery,  instead  of  from  the 
aorta,  while  the  left  comes  from  the  latter:  occasionally  they 
have  a  common  root. 

On  either  side  they  follow  the  course  of  the  bronchia  into  the 
substance  of  the  lung;  and  are  distributed  along  with  it,  by  ra- 
mifications which  become  successively  finer  and  finer,  and 
anastomose  with  the  pulmonary  artery;  after  the  manner  men- 
tioned in  the  description  of  the  lungs.  Before  they  enter  the 
latter,  they  send  some  small  ramifications  to  the  posterior  me- 
diastinum, to  the  pericardium,  and  to  the  black  bronchial  glands. 

The  (Esophageal  Arteries  (Jlrterise  GSsophagea)  are  gene- 
rally five  or  six  small  twigs  which  come  successively  from  the 
descending  thoracic  aorta.  They  ramify  minutely  in  the  sub- 
stance of  the  oesophagus,  communicating  freely  with  each  other: 
the  lowest  of  them  also  anastomoses  around  the  cardia  with  the 
superior  coronary  artery  of  the  stomach. 

The  Posterior  Arteries  of  the  Mediastinum,  (Jlrterise  Me* 
diastinales  Posteriores,)  are  numerous  and  small;  they  come 
from  the  anterior  face  of  the  aorta,  as  well  as  from  the  branches 
last  mentioned;  and  are  spent  upon  the  posterior  mediastinum, 
and  upon  its  contents. 

The  Intercostal  Arteries  (JlrtericR  Intercostales  Inferiores 
*ftortic(R)  of  the  aorta  supply  the  ten  lower  intercostal  spaces  on 
each  side,  as  the  two  upper  ones  are  supplied  by  the  subclavian 
artery.  There  is  commonly  an  intercostal  artery  arising  dis- 
tinctly from  the  aorta  for  each  space,  but  sometimes  two  of 
them  arise  from  a  common  trunk.  Those  for  the  right  side 
having  to  cross  the  spine  behind  the  oesophagus  and  the  vena 
azygos,  are,  of  course,  longer  than  such  as  belong  to  the  left. 
The  upper  ones  on  either  side  have  to  ascend,  in  order  to  reach 
their  destination. 

Each  artery  joins  the  rib  near  its  tubercle,  and  goes  along  the 
groove  in  its  lower  margin,  between  the  external  and  the  inter- 
nal intercostal  muscles,  for  two-thirds  of  the  length  of  the  rib. 
VOL.  II— 29 


222  CIRCULATORY  SYSTEM. 

It  then  abandons  the  groove,  and  divides  into  several  branches, 
which  go  to  the  intercostal  muscles  and  contiguous  parts,  and 
anastomose  in  front  with  the  internal  mammary  artery. 

As  each  intercostal  artery  passes  the  head  of  the  rib,  it  sends 
a  branch  backwards,  (ramus  dorsalis,)  between  -the  transverse 
processes  of  the  adjoining  vertebrae,  which  penetrates  to  the 
posterior  face  of  the  trunk,  and  is  distributed  to  the  muscles  and 
skin  on  the  side  of  the  spine.  A  ramification  from  this  branch 
enters  the  intervertebral  foramen,  and  is  spent  upon  the  medulla 
spinalis  and  its  membranes. 

Each  intercostal  artery  also  gives  off,  about  the  middle  of  the 
rib,  a  branch,  (ramus  costalis  inferior?)  much  smaller  than  the 
trunk.  This  branch  advances  along  the  upper  margin  of  the 
rib  below,  and  gives  ramifications  to  its  periosteum  and  to  the 
adjacent  intercostal  muscles. 

The  last  intercostal  artery  is  remarkable  for  its  size.  Its  ori- 
gin^is  concealed  by  the  small  muscle  of  the  diaphragm,  to  which 
it  gives  some  ramifications:  it  then  passes,  at  the  under  margin 
of  the  rib,  behind  the  upper  end  of  the  quadratus  lumborum 
muscle,  where  it  divides  into  three  branches;  one  of  which  goes 
transversely  to  the  broad  muscles  of  the  abdomen;  while  the 
other  two  descend  between  the  oblique  and  transverse  muscles 
towards  the  crest  of  the  ilium,  where  they  anastomose  with  the 
lumbar  arteries,  and  with  the  circumflexa  ilii.  . 

SECT.  V. — OF  THE  BRANCHES  OF  THE  ABDOMINAL  AORTA. 

The  Phrenic  Arteries  (Arteries,  Phrenicce)  are  two  in  num- 
ber, one  for  the  right  and  the  other  for  the  left  side  of  the  dia- 
phragm. They  arise  singly,  but  sometimes  by  a  common  trunk, 
from  the  front  of  the  aorta,  immediately  on  the  latter  showing 
itself  in  the  abdomen,  between  the  crura  of  the  diaphragm;  con- 
sequently, just  below  the  crossing  of  the  muscular  fibres,  which 
lakes  place  between  the  foramen  for  the  aorta  and  that  for  the 
O3sophagus. 

The  phrenic  arteries  ascend  along  the  lesser  muscle  of  the 
diaphragm,  and  give  some  ramifications  to  it  and  to  the  capsulae 
rcnalcs.  They  then  divide  each  into  two  leading  trunks,  which 
arc  distributed  over  the  diaphragm,  principally  on  its  concave 


BRANCHES  OP  THE  ABDOMINAL  AORTA.  223 

surface.     Some  small  ramifications  from  them  go  to  the  liver 
and  to  the  lower  part  of  the  oesophagus. 

The  two  phrenic  arteries  anastomose  with  each  other:  also, 
with  the  superior  phrenics,  coming  from  the  internal  mammary; 
and  with  the  intercostals.  Sometimes  one  or  both  of  them  come 
from  the  coeliac  artery,  or  its  branches. 

The  Coeliac  Artery  (Jlrteria  Ccdiaca)  is  the  next  branch  of 
the  abdominal  aorta,  and  arises  immediately  below  the  phrenics, 
between  the  pillars  of  the  diaphragm,  opposite  the  junction  of 
the  last  dorsal  with  the  first  lumbar  vertebra.  It  is  a  very  large 
trunk,  and  goes  off  at  right  angles,  being  placed  between  the 
left  lobe  of  the  liver  and  the  superior  margin  of  the  pancreas. 
When  it  is  only  half  an  inch  long,  it  is  split  into  three  trunks, 
the  Gastric,  the  Hepatic  and  the  Splenic;  this  division  is  the 
Tripus  Halleri. 

The  Gastric  Artery  (Jlrteria  Gastrica,  Coronaria  Ventri- 
culi)  is  the  smallest  of  the  three  trunks,  and  frequently  arises 
from  one  of  the  others.  It  advances  forwards  and  towards  the 
left,  in  order  to  reach  the  small  curvature  of  the  stomach,  the 
course  of  which  it  pursues  to  the  pylorus,  between  the  two  lami- 
nae of  the  little  omentum.  It  gives  off  the  following  branches:— 

a.  Ramifications  to    the  oesophagus,  some  of  which  ascend 
along  it  into  the  posterior  mediastinum,  and  anastomose  there 
with  the  similar  branches  coming  from  the  aorta;  others  go  trans- 
versely, so  as  to  surround  the  cardia,  reach  the  greater  end  of 

.the  stomach,  and  anastomose  with  the  vasa  brevia. 

b.  The  ramifications  to  the  stomach  are  abundant,  but  of  an 
indeterminate  number,  and  arising  along  its  lesser  curvature,  are 
distributed  in  winding  branches  to  the  anterior  and  the  posterior 
surfaces  of  this  viscus,  between  its  membranes. 

c.  Not  unfrequently  the  artery  which  supplies  the  left  lobe 
of  the  liver  is  a  branch  from  the  gastric,  in  which  case  the  lat- 
ter/is much  larger  than  usual. 

2.  The  Hepatic  Artery  (<flrteria  Hepaticd)  is  generally  con- 
siderably larger  than  the  gastric,  and  inclines  towards  the  right 
side,  in  order  to  reach  the  liver,  which  it  does  through  the  cap- 
sule of  Glisson.  It  send  off  the  following  branches: — 


224  CIRCULATORY   SYSTEM. 

a.  The  Right  Gastric  or  Gastro-Epiploic  Artery  (*Arteria 
Gastrica  Dextra]  comes  from  it  near  the  pylorus,  and  descend- 
ing between  the  duodenum  and  pancreas,  reaches  the  great- 
er curvature  of  the  stomach,  to  the  right  half  of  which,  and  to 
the  corresponding  part  of  the  great  omentum,  it  is  distributed. 
In  the  early  part  of  its  course,  the  right  gastric  detaches  some 
small  ramifications  to  the  pylorus  (arttrm  pyloriccc;)  also,  to 
the  duodenum  and  to  the  pancreas  (art.  pancrealico  duode- 
nales.)  The  latter  communicate,  by  very  free  anastomoses,  with 
the  superior  mesenteric  artery. 

After  having  sent  off  this  branch,  the  hepatic  artery  advances 
to  the  transverse  fissure  of  the  liver,  in  front  of  and  to  the  left 
of  the  vena  portarum.  It  then  divides  into  a  right  and  a  left 
branch.  The  former  sends  off  a  ramification  to  the  gall-bladder, 
(art.  Cystica,}  which  first  reaches  its  neck,  and  is  distributed, 
by  many  arterioles,  upon  the  parietes  of  this  reservoir;  the  right 
branch  then  penetrates  deeply  into  the  transverse  fissure,  and  is 
distributed,  by  many  ramifications,  throughout  the  right  lobe  of 
the  liver.  The  left  branch  of  the  hepatic  artery  is  distributed, 
in  the  same  manner,  throughout  the  left  lobe  of  the  liver. 

3.  The  Splenic  Artery  (Jlrteria  Splenicd)  is  larger  in  the 
adult  than  either  of  the  other  two  branches  of  the  cceliac,  and 
goes  to  the  spleen  along  the  superior  margin  of  the  pancreas, 
performing,  in  this  course,  several  considerable  flexuosities.  It 
gives  off  the  following  branches: — 

a.  The  Pancreatic  Arteries  (Art.  PancreaticK  Media  et  Sinis- 
trce)  come  successively  from  its  inferior  margin,  as  it  goes  along 
the  pancreas.     Their  number  and  size  are  variable,  but  com- 
monly they  are  not  bigger  than  a  knitting  needle:  they  pene- 
trate perpendicularly  into  the  pancreas,  and  then  subdivide  mi- 
nutely in  furnishing  its  structure. 

b.  The  Left  Gastric  Artery  (*ftrt.  Gastrica  Sinistra,  Gaslro- 
epiploica  Sinistra)  comes  from  the  left  extremity  of  the  splenic, 
and  is  about  the  same  size  with  the  right  gastric  artery,  but  some- 
times larger.     It  attaches  itself  to  the  left  extremity  of  the  sto- 
mach, and  goes  along  the  left  half  of  its  greater  curvature,  ter- 
minating by  an.  anastomosis  with  the  right  gastric  artery.     In 
this  course,  it  detaches  ramifications  to  the  front  and  to  the  back 
of  the  stomach,  and  to  the  omentum  majus. 


BRANCHES  or  THE  ABDOMINAL  AORTA.      225 

£.  The  Short  Vessels  ( Vasa  Brevia,  Jlrt.  Gastricce  Breves] 
come  from  the  splenic,  immediately  before  it  enters  the  spleen, 
and  after  it  has  subdivided  for  that  purpose.  They  are  five  or 
six  in  number,  and  are  distributed  upon  the  greater  extremity 
of  the  stomach,  between  the  cardia  and  the  left  gastric  artery. 
The  anastomoses  between  the  several  arteries  of  the  stomach 
are  so  free,  that  a  fine  injection  pushed  into  one,  readily  finds 
its  way  into  all  the  others. 

The  splenic  artery,  when  it  gets  to  the  left  end  of  the  pan- 
creas, is  divided  into  a  cluster  of  branches,  and  in  that  condition 
enters  the  fissure  of  the  spleen,  throughout  the  interior  of  which 
it  is  divided  into  an  infinitude  of  ramifications. 

The  Superior  Mesenteric  Artery  (Jlrteria  Mesenterica  Su- 
perior) arises  from  the  aorta,  while  the  latter  is  still  engaged, 
between  the  crura  of  the  diaphragm.  It  is  about  the  same  size 
as  the  coeliac,  and  comes  off  half  an  inch  below  it.  It  is  distri- 
buted to  all  the  small  intestine  and  to  the  right  side  of  the  large 
one  after  the  following  manner:  it  first  passes  behind  the  pan- 
creas, and  then  in  front  of  the  duodenum,  to  reach  the  root  of 
the  mesentery,  between  the  two  laminae  of  which  it  divides 
and  subdivides  into  several  series  of  arches,  one  after  another: 
they  become  successively  smaller  and  more  numerous  till  they 
reach  the  margin  of  the  intestine,  where  they  cease  by  sending 
a  great  many  small  parallel  branches. 

The  trunk  of  the  superior  mesenteric  artery,  in  descending 
between  the  laminae  of  the  mesentery,  describes  a  considerable 
curvature,  the  convexity  of  which  is  to  the  left  side  and  down- 
wards, while  its  concavity  is  in  a  contrary  direction.  It  is  from 
the  convexity  of  this  trunk,  that  from  fifteen  to  twenty  large 
branches  are  sent  off  successively  to  form  the  roots  of  the  first 
row  of  arterial  arches.  These  branches  are  shorter,  and  gene- 
rally somewhat  smaller,  the  lower  down  they  arise;  and  their 
origins  very  closely  succeed  each  other. 

Besides  the  preceding  branches,  the  superior  mesenteric  ar- 
tery send-off  the  following: 

Near  its  root  several  small  ramifications  arise,  which  go  to 
the  duodenum  and  to  the  pancreas,  and  anastomose  there  with 
other  arteries  supplying  the  same  organs. 


CIRCULATORY  SYSTEM. 

From  about  the  middle  of  the  concavity  of  the  superior  me- 
senteric artery,  arise  the  three  Colic  arteries  called  Ileo-colica, 
Colica  Dextra,  and  Colica  Media:  the  first  supplies  a  cluster  of 
branches  to  the  lower  part  of  the  ileum  and  to  the  head  of  the 
colon,  anastomosing  on  the  left  with  the  last  of  the  small  in- 
testinal arteries  and  on  the  right  with  the  colica  dextra:  the 
Colica  Dextra  is  smaller  than  either  of  the  other  two  branches, 
and  going  between  the  laminae  of  the  mesocolon,  supplies  the 
ascending  portion  of  the  colon  by  dividing  into  two  principal 
branches,  one  of  which  anastomoses  with  the  ileo-colic  artery, 
and  the  other  with  the  colica  media:  the  Colica  Media,  situated 
between  the  laminae  of  the  transverse  mesocolon,  and  arising 
higher  up  than  the  colica  dextra,  advances  forwards  and  divides 
Into  two  principal  trunks;  one  of  which  supplies  that  part  of 
the  colon  in  the  right  hypochondriac  region,  and  the  other  the 
remainder  of  its  transverse  portion,  forming  an  anastomosis 
with  the  colica  superior  of  the  inferior  mesenteric  artery.  The 
arteries  which  supply  the  colon  differ  from  those  supplying  the 
small  intestines,  in  forming  but  one  row  of  arches;  which,  in 
fact,  are  produced  by  the  anastomoses  spoken  of,  and  have,  there- 
fore, extremely  large  meshes.  From  the  convexity  of  these 
arches,  many  parallel  branches  run  out  to  supply  the  colon,  and 
are  very  minutely  distributed  to  it. 

The  Capsular  Arteries,  the  Emulgents,  and  the  Spermatics, 
arise  from  the  aorta,  between  the  superior  and  the  inferior  me- 
senteries. But  they  will  be  described  after  the  inferior  mesen- 
teric, so  as  to  keep  together  the  account  of  the  arteries  of  the 
intestines. 

The  Inferior  Mesenteric,  Artery  (Jlrt,  Mesenterica  Inferior) 
generally  arises  about  one  inch  above  the  division  of  the  aorta 
into  the  two  primitive  iliacs,  and  is  much  smaller  than  the  su- 
perior Mesenteric.  It  inclines  downwards  to  the  left  side,  and 
gets  between  the  lamina  of  the  mesocolon;  it  then  divides  into 
three  branches,  called  the  Left  Colic  Arteries,  from  their  dis- 
tribution to  the  left  side  of  the  colon.  From  their  relative  si- 
tuation to  each  other,  they  are  distinguished  into  the  Superior, 
the  Middle,  and  the  Inferior;  sometimes,  however,  there  are 
but  two  of  these  trunks. 


BRANCHES  OF  THE  ABDOMINAL  AORTA.         227 

The  Superior  Colic  (Art.  Colica  Sinistra  Superior)  goes  ho- 
rizontally towards  the  colon  in  the  left  lumbar  region;  having 
got  near  the  intestine  it  divides  into  two  branches,  one  of  which 
ascends  to  the  transverse  colon  to  form  the  anastomosis  with 
the  Colica  Media  of  the  upper  mesenteric,  while  the  other,  de- 
scends to  unite  with  the  colica  media  sinistra.  The  middle 
Colic  Artery  (Jlrt.  Colica  Sinistra  Media]  is  sometimes  a 
branch  of  the  superior,  and  is  occasionally  wanting;  it  goes  to- 
wards the  upper  part  of  the  sigmoid  flexure  of  the  colon,  and 
then  bifurcates;  one  branch  ascends'  to  form  by  anastomosis  an 
arch  with  the  superior  colic,  while  the  other  branch  descends 
to  join  the  lower  colic  artery.  The  Inferior  Colic  Artery  (*flrt. 
Colica  Sinistra  Inferior)  goes  towards  the  middle  of  the  sig- 
moid flexure  of  the  colon,  and  there,  like  the  preceding,  divides 
into  two  branches;  one  anastomoses  with  the  artery  above,  while 
the  other  joins  with  the  arteries  which  go  to  the  rectum  from? 
the  inferior  mesenteric. 

The  Superior  Ifemorrhoidal  Artery  (Art.  H&morrhoidea  Supe- 
rior, Intern  a)  is  the  lowest  and  the  last  branch  of  the  inferior  me- 
senteric. It  descends  between  the  laminae  of  the  mesorectum, 
and  is  divided  into  two  symmetrical  trunks,  which  radiate  by 
dividing  and  subdividing  on  the  side  of  the  rectum,  and  are  dis- 
persed in  very  fine  and  numerous  branches  throughout  its  sub- 
stance :  and  anastomose  with  the  middle  and  the  inferior  hae.»- 
morrhoida!  arteries,  also  with  the  lateral  sacral. 

The  Capsular  Arteries  (Art.  Capsulares)  arise  frequently  from 
the  aorta  just  below  the  superior  mesenteric ;  but  quite  as  often, 
if  not  more  so,  from  the  emulgents.  They  are  not  larger  than 
a  crow's  quill,  and  vary  from  one  to  three  on  either  side,  gene- 
rally, however,  not  exceeding  one :  when  they  do,  they  are  pro- 
portionably  small.  Passing  horizontally  outwards,  they  divide 
into  several  small  ramifications,  which  terminate  in  the  capsule 
renales.  Some  of  their  branches  go  to  the  lesser  muscle  of  the 
diaphragm. 

The  Emulgent  Arteries  (Art.  Emulgentes,  Renales)  are  two  i» 
number,  one  for  each  kidney,  but  sometimes  more.  They  are 
large  and  short,  arise  from  the  side  of  the  aorta  immediately  be- 


228  CIRCULATORY  SYSTEM. 

low  the  superior  mesenteric,  and  pass  outwardly  in  a  horizontal 
direction.  The  right  one  is  longer  than  the  left,  somewhat  lower 
down,  and  passes  behind  the  ascending  cava.  They  are  both,  in 
their  course,  from  the  aorta  to  the  kidney,  covered  in  front  by 
the  emulgent  vein,  and  have  to  pass  through  a  mass  of  adipose 
matter. 

The  emulgent  sends  off  some  fine  ramifications  to  the  adipose 
matter,  which  surrounds  it,  and  before  it  reaches  the  fissure  of 
the  kidney  divides  into  three  or  four  branches,  preparatory  to  its 
introduction  into  this  gland ;  upon  the  structure  of  which  it  is  ul- 
timately distributed  by  .very  fine  branches. 

The  Spermatic  Arteries  (Arlerm  Spermaticce,  Seminales)  arise 
from  the  aorta  somewhat  below  the  emulgents,  but  in  some 
cases  from  the  latter  themselves.  They  are  two  in  number,  one 
on  each  side,  and  are  about  the  size  of  a  crow  quill  in  the  male 
subject,  but  smaller  in  the  female.  One  comes  off  generally 
higher  up  than  the  other ;  they  then  descend  on  the  sides  of  the 
vertebral  column  before  the  psoae  muscles,  and  cross  in  front  of 
the  ureters,  being  in  all  this  course  behind  the  peritoneum.  They 
are  tortuous,  and  shortly  after  their  origin  begin  to  adhere  to  the 
spermatic  veins,  which  adhesion  is  continued  to  the  testicle. 

The  branches  that  the  spermatic  artery  sends  off  in  the  abdo- 
men are  inconsiderable,  consisting  in  very  fine  twigs  to  the  adja- 
cent adipose  matter,  to  the  lymphatic  glands,  to  the  ureter,  and 
to  the  peritoneum.  In  the  male  subject,  it  passes  with  the  vas 
deferens,  through  the  abdominal  canal,  and  reaching  the  testicle 
divides  into  branches  which  supply  the  body  of  this  gland  and 
the  epididymis.  In  descending  from  the  external  ring  to  the  tes- 
tis,  some  small  ramifications,  to  the  adjacent  parts  leave  it.  In 
the  female,  the  spermatic  artery  does  not  leave  the  cavity  of  the 
abdomen,  but  descending  into  the  pelvis,  gets  between  the  lami- 
nae of  the  broad  ligament  to  the  ovarium,  and  is  spent  principally 
upon  the  latter.  Some  of  its  branches  go  to  the  Fallopian  Tube, 
to  the  Round  Ligament  of  the  uterus,  and  to  the  sides  of  the  lat- 
ter, where  they  anastomose  with  the  uterine  arteries. 

The  Lumbar  Arteries  (Arteries  Lumbares)  are  commonly  five 
in  number  on  either  side,  but  seldom  less  than  three,  and,  in  their 
course  outwards,  correspond  with  the  intercostal  arteries.  They 


BRANCHES  OF  THE  ABDOMINAL  AORTA.  229 

are  much  larger  than  the  latter.  They  arise  in  pairs,  from  the 
posterior  external  face  of  the  aorta,  at  a  point  corresponding 
with  the  middle  of  the  bodies  of  the  four  upper  lumbar  vertebrae ; 
and  pass  outwards  between  the  fasciculi  of  the  psoas  magnus 
muscle,  to  which,  to  the  quadratus  lumborum,  and  the  bodies  of 
the  vertebras,  they  distribute  several  branches.  Sometimes  each 
pair  arises  by  a  common  trunk  from  the  posterior  face  of  the 
aorta.  As  the  latter  terminates  at  the  fourth  lumbar  vertebra, 
the  fifth  lumbar  artery  is  a  branch  from  the  fourth  in  most  in- 
stances. At  the  base  of  the  transverse  process  each  artery  di- 
vides into  two  branches,  a  posterior  or  dorsal  one,  and  an  ante- 
rior or  lumbar. 

The  dorsal  branch,  which  is  smaller  than  the  other,  detaches 
a  ramification  through  the  intervertebral  foramen  to  the  lower 
part  of  the  medulla  spinalis  and  to  the  cauda  equina :  it  then  gets 
to  the  back,  where  it  is  spent  upon  the  muscles  near  the  spine. 
The  anterior  lumbar  branch  advances  between  the  broad  mus- 
cles of  the  abdomen,  to  which  it  is  distributed ;  and  runs  for- 
wards far  enough  to  anastomose  with  the  epigastric  artery. 

The  first  lumbar  artery  is  small,  and  sometimes  comes  from 
the  last  intercostal ;  it  goes  a  little  below  the  inferior  margin  of 
the  last  rib,  and  then  descends  almost  vertically  between  the  pe- 
ritoneum and  the  transversus  abdominis  muscle.  The  lower  lum- 
bar arteries  anastomose  with  the  circumflexa  ilii,  and  with  the 
superficial  branches  of  the  gluteal. 

The  Middle  Sacral  Artery  (Arteria  Sacra  Media)  is  generally 
not  so  large  as  a  lumbar ;  it  arises  from  the  centre  of  the  bifur- 
cation of  the  aorta  into  the  two  primitive  iliacs,  or  else  a  line  or 
two  above  it,  behind.  It  descends,  in  front  of  the  middle  line  of 
the  fifth  lumbar  vertebra  and  of  the  sacrum,  to  the  coccyx, 
adhering  to  the  surface  of  these  bones,  and  performing  some 
flexuosities. 

It  sometimes  happens  that  the  last  pair  of  lumbar  arteries 
come  from  it,  or  at  least  one,  according  to  Meckel,  more  com- 
monly the  left :  in  which  case  the  sacral  is  of  unusual  size.  The 
sacral  afterwards  sends  off,  to  the  right  and  left,  a  pair  of 
branches  for  each  pair  of  sacral  foramina.  They  run  across  the 
sacrum,  send  branches  to  it,  anastomose  with  the  lateral, sacral 
VOL.  II.— 30 


230  CIRCULATORY  SYSTEM. 

arteries,  and  then  penetrate  to  the  cauda  equina.  The  middle 
sacral  artery  is  lost  at  the  inferior  end  of  the  coccyx,  in  the  fat 
and  cellular  tissue  of  the  part. 


SECT.  VI. — OF  THE  PRIMITIVE  ILIAC  ARTERIES,  AND  THEIR  BRANCHES. 

The  Primitive  Iliac  Arteries,  (Art.  Iliac®  Primitives,  communes,) 
one  on  each  side,  are,  as  mentioned,  the  terminating  trunks  of 
the  abdominal  aorta.  They  extend  from  the  lower  part  of  the 
fourth  lumbar  vertebra  to  the  sacro-iliac  junction,  or  near  it, 
where  they  divide  into  two  trunks,  the  Internal  and  the  External 
Iliac. 

The  primitive  iliac  is  bounded  on  the  outer  side  by  the  psoas 
magnus  muscle,  and  behind  by  the  primitive  iliac  vein;  it  is 
crossed  at  its  lower  part  by  the  ureter.  No  branches  deserving 
of  especial  notice  are  sent  from  it  before  it  bifurcates ;  such  as 
exist  are  very  small,  and  go  simply  to  the  parts  immediately  con- 
tiguous. The  right  artery  crosses  in  front  of  the  root  of  the  left 
iliac  vein. 

SECT.  VII. — OF  THE  INTERNAL  ILIAC  ARTERY,  AND  ITS  BRANCHES. 

The  Internal  Iliac  Artery  (Art.  Iliaca  Internet,  Hypogastrica) 
descends  from  the  front  upper  part  of  the  sacro-iliac  junction,  to 
the  lower  part  of  the  same  articulation.  In  this  descent,  it  is 
bounded  behind  by  the  sacral  plexus  of  nerves,  and  gives  off  se- 
veral arterial  trunks ;  but  the  manner  by  which  the  last  is  ac- 
complished is  much  varied  in  different  subjects.  For  the  most 
part,  it  is  an  inch  or  more  long  before  any  important  branches 
leave  it ;  it  is,  then  frequently  divided  into  two  principal  trunks, 
an  anterior  and  a  posterior,  from  which  proceed  the  several 
branches  that  supply  the  internal  and  the  external  parts  of  the 
pelvis.  The  rule  of  origin  of  the  secondary  trunks  from  these 
two  principal  ones,  even  when  the  latter  exist,  is  not  fixed,  for 
sometimes  they  arise  from  one,  sometimes  from  the  other,  and 
then  again  from  the  trunk  of  the  hypogastric  itself. 

The  Ilio-Lumbar  Artery  (Art.  llio-Lumb aris^is  commonly  the 


INTERNAL  ILIAC  ARTERY,  AND  ITS  BRANCHES.  231 

first  branch  of  the  hypogastric,  or  of  its  posterior  trunk.  It  as- 
cends outwards  and  backwards  behind  the  psoas  magnus  mus- 
cle, and  there  divides  into  two  branches,  a  superior  and  an  in- 
ferior. The  former  continues  to  ascend  between  the  psoas 
magnus  and  the  iliacus  interims  muscles,  to  which,  and  to  the 
quadratus  lumborum,  it  distributes  branches:  it  also  sends  rami- 
fications into  the  spinal  cavity,  and  anastomoses  with  the  lower 
lumbar  arteries;  sometimes  it  supplies  the  place  of  the  last  lum- 
bar entirely.  The  inferior  branch,  going  outwardly,  is  divided 
into  two  orders  of  ramifications  which  supply  the  iliacus  inter- 
ims muscle,  on  its  surface  and  more  deeply;  also  the  os  ilium  by 
a  ramuscle  which  penetrates  the  nutritious  foramen  of  the  latter. 
The  inferior  branch  anastomoses  with  the  circumflexa  ilii  of  the 
external  iliac. 

The  Lateral  Sacral  Arteries  (Arteries  Sacrce  Laterales)  arise 
next,  either  from  the  hypogastric  or  from  its  posterior  trunk : 
their  number  is  commonly  equal  to  that  of  the  foramina  on  the 
side  of  the  sacrum  in  front,  though  they  come  from  only  one  or 
two  roots.  They  cross  the  front  of  the  sacrum,  and  divide  into 
branches,  some  of  which  anastomose  with  the  middle,  sacral 
artery,  while  others  enter  the  foramina  of  the  sacrum,  to  be 
spent  on  the  lower  part  of  the  cauda  equina. 

The  Obturator  Artery  (Arteria  Obturatoria)  comes  commonly 
from  the  hypogastric  or  from  one  of  its  principal  trunks ;  in  some 
cases  it  arises  from  the  epigastric  or  from  the  external  iliac, 
near  Poupart's  ligament.  In  the  first  cases  it  passes  forwards 
parallel  with  the  brim  of  the  pelvis,  and  in  the  latter  cases  it  de- 
scends behind  the  superior  rarnus  of  the  pnbes.  Whatever  may 
be  the  condition  of  its  organ,  it  gets  from  the  pelvis  through  the 
upper  part  of  the  thyroid  foramen  over  the  superior  margin  of 
the  obturator  internus  muscle,  having  previously  sent  off  some 
inconsiderable  ramifications  to  the  periosteum  and  the  contiguous 
muscles. 

It  emerges  from  the  pelvis  on  the  upper  margin  of  the  obtu- 
rator externus  muscle,  and  then  divides  into  two  principal  trunks. 
The  posterior  despends  along  the  external  margin  of  the  obtu- 
rator externus  muscle,  to  which  it  gives  ramifications;  it  like- 


232  CIRCULATORY  SYSTEM. 

wise  sends  some  branches  to  the  heads  of  the  muscles  coming 
from  the  tuber  of  the  ischium,  and  thereby  anastomoses  with  the 
sciatic  artery;  other  branches  are  spent  upon  the  hip  joint,  one 
of  which  gets  into  the  cavity  of  the  latter  through  the  notch  at 
the  lower  part  of  the  acetabulum,  and  is  spent  upon  the  adipose 
matter  in  its  bottom.  The  anterior  branch  goes  to  the  heads  of 
the  adductor  muscles,  to  the  pectineus,  to  the  obturator  externus, 
and  to  the  integuments  of  the  upper  internal  part  of  the  thigh. 
Near  its  origin  this  branch  sends  a  ramification  along  the  inter- 
nal margin  of  the  thyroid  foramen  to  anastomose  with  the  pos- 
terior branch,  so  that  the  foramen  is  surrounded  by  an  arterial 

circle. 

i 

The  Middle  Ifemorrhoidal  Artery  (Art.  Hcemorrhoidea  Media) 
varies  in  its  origin,  being  sometimes  from  the  hypogastric  itself, 
and,  on  other  occasions,  from  one  of  its  branches,  as  the  gluteal, 
ischiatic,  &c.  It  descends  on  the  fore  part  of  the  rectum,  op- 
posite the  lower  fund  us  of  the  bladder  in  the  male,  and  is  distri- 
buted by  branches  to  the  rectum,  to  the  vesiculae  seminales,  and 
to  the  prostate  gland.  In  the  female  it  dispenses  branches  to 
the  vagina.  It  is  called  middle,  from  its  position  between  the 
upper  and  the  lower  haemorrhoidal  arteries. 

In  both  sexes,  the  branches  which  it  sends  to  other  parts  be- 
sides the  rectum,  frequently  arise  from  other  arteries,  and  in  a 
manner  which  causes  them  to  have  distinct  appellations,  as  va- 
ginal, &c. 

The  Vesical  Arteries  (Arteries,  Vesicales)  consist  in  several  ra- 
mifications, coming  from  what  was  the  umbilical  artery  of  the 
foetus,  but  which,  in  the  adult,  with  the  exception  of  a  short  space 
near  its  origin,  is  converted  into  a  ligamentous  chord.  These 
branches  ramify  upon  the  parietes  of  the  bladder ;  one  of  them, 
more  voluminous  than  any  other,  and  called,  by  M.  Chaussier, 
vesico-prostatic,  gains  the  lower  fundus  of  the  bladder ;  sends 
branches  to  it,  to  the  prostate,  to  the  vesiculae  seminales,  and  to 
the  commencement  of  the  urethra. 

The  Uterine  Artery  (Arteria  Uterina)  arises  from  the  hypogas- 
tric, or  one  of  its  branches,  near  the  vesical,  sometimes  before, 


INTERNAL  ILIAC  ARTERY,  AND  ITS  BRANCHES.  233 

and  on  other  occasions  subsequent  to  them.  Being  peculiar  to 
the  female  sex,  its  size  varies  according  to  the  individual,  being 
in  a  state  of  pregnancy  or  not :  in  the  latter  stages  of  gestation 
it  is  as  large  as  any  other  branch  of  the  hypogastric. 

It  goes  inwards  towards  the  superior  part  of  the  vagina,  to 
which  it  gives  some  ramifications ;  it  then  ascends  between  the 
laminae  of  the  broad  ligament,  in  a  tortuous  manner  along  the 
side  of  the  uterus,  and  divides  into  many  branches  which  are 
distributed  through  the  tissue  of  this  organ.  It  anastomoses  with 
the  corresponding  arteries  of  the  other  side,  and  with  the  branches 
of  the  spermatic  artery  which  go  to  the  Fallopian  tube  and  to 
the  ovarium. 

Besides  the  preceding,  the  hypogastric  artery  sends  off  two 
large  branches,  the  Gluteal  and  the  Ischiatic,  which  terminate  it. 
In  many  subjects  they  are  the  direct  continuation  of  the  two  pri- 
mitive trunks,  into  which  the  hypogastric  is  frequently  originally 
divided. 

The  Gluteal  Artery,  (Arteria  Glutea,)  shortly  after  its  origin, 
issues  from  the  pelvis  above  the  pyriformis  muscle,  at  the  upper 
part  of  the  ischiatic  foramen,  where  it  adheres  closely  to  the  edge 
of  the  bone.  When  it  first  gets  to  the  dorsum  of  the  ilium,  it  is 
covered  by  the  gluteus  maximus  muscle,  and  lies  at  the  poste- 
rior margin  of  the  gluteus  minimus,  precisely  under  a  line  drawn 
from  the  posterior  superior  spinous  process  to  the  top  of  the  tro- 
chanter  major.  It  almost  immediately  afterwards  divides  into 
two  principal  trunks. 

One  of  these  trunks,  the  more  superficial,  advances  between 
the  gluteus  medius  and  the  maximus,  and  distributes  branches  to 
them ;  also,  to  the  posterior  margin  of  the  maximus,  where  it 
comes  from  the  posterior  sacro-sciatic  ligament.  The  more 
deeply-seated  trunk  goes  forwards  between  the  gluteus  medius 
and  minimus,  and  subdivides  into  three  orders  of  branches  for 
their  supply.  One  set  follows  the  superior  margin  of  the  gluteus 
minimus  towards  the  anterior  superior  spinous  process ;  another 
set  passes  nearer  the  middle  of  the  gluteus  minimus ;  and  the 
third  set  still  lower  down  upon  the  dorsum  of  the  ilium,  above 
the  acetabulum ;  some  of  the  ramifications  go  to  the  capsular  li- 


234  CIRCULATORY  SYSTEM. 

gament  of  the  joint,  where  they  anastomose  with  branches  from 
the  femoral  artery. 

The  Ischiatic  Artery  (Arteria  Ischiadica)  is  somewhat  smaller 
than  the  gluteal,  but  looks  rather  more  like  the  continuation  of 
the  hypogastric.  It  descends  between  the  rectum  and  the  pyri- 
formis  muscle,  and  issues  under  the  lower  margin  of  the  latter, 
out  of  the  pelvis,  being  there  placed  in  front  of  the  sciatic  nerve. 
It  goes  downwards  on  the  back  of  the  thigh,  between  the  tro- 
chanter  major  and  the  tuberosity  of  the  ischium,  being  at  the  in- 
ternal edge  of  the  sciatic  nerve,  and  on  the  posterior  face  of  the 
small  rotator  muscles  of  the  thigh.  It  sends  off  in  the  pelvis  the 
Internal  Pudic  Artery,  and  also  some  inconstant  branches,  of 
small  size,  to  the  viscera  within  the  pelvis ;  when  it  has  emerged 
from  the  latter,  it  detaches  some  considerable  branches  to  the  ori- 
gin and  to  the  inferior  margin  of  the  gluteus  magnus  muscle,  and  to 
the  small  rotator  muscles.  The  branch  which  may  be  consi- 
dered as  the  continued  trunk  of  the  ischiatic,  descending  on  the 
f-posterior  face  of  the  thigh,  along  with  the  sciatic  nerve,  under 
the  hamstring  muscles,  is  lost  in  ramifications  to  them,  and  by 
anastomoses  with  the  perforating  arteries. 

The<  Internal  Pudic  Artery,  (Arteria  Pudica  Internal)  though  a 
branch  of  the  ischiatic,  is  only  in  a  slight  degree  smaller.  It 
arises  a  little  above  the  spinous  process  of  the  ischium,  in  the 
pelvis,  in  front  of  the  sciatic  plexus,  and  getting  from  the  pelvis 
between  the  anterior  sacro-sciatic  ligament  and  the  inferior 
margin  of  the  pyriformis  muscle,  it  passes  over  the  posterior 
face  of  the  anterior  sacro-sciatic  ligament,  at  the  spinous  process 
of  the  ischium.  It  immediately  afterwards  returns  into  the  ca- 
vity of  the  pelvis,  between  the  two  sacro-sciatic  ligaments,  at 
the  place  where  the  obturator  internus  muscle  winds  over  the 
ischium ;  it  then  winds  along  the  internal  face  of  the  latter  bone 
and  of  its  ascending  ramus,  at  the  inferior  margin  of  the  obtu- 
rator internus  muscle ;  and  continues  on  the  internal  face  of  the 
ramus  of  the  pubes,  between  the  two  laminae  of  the  triangular 
ligament,  above  the  crus  of  the  penis  to  the  symphysis  of  the 
pubes. 


INTERNAL  ILIAC  ARTERY,  AND  ITS  BRANCHES.  235 

In  this  course  the  Internal  Pudic  Artery  detaches  several  im- 
portant branches,  in  the  following  order  :— 

a.  A  ramification  along  the  inferior  margin  of  the  pyriformis, 
to  this  muscle  and  to  the  parts  on  the  posterior  face  of  the  neck 
of  the  os  femoris,  where  it  anastomoses  with  the  other  arteries 
of  this  region. 

b.  The  Lower  Haemorrhoidal  Artery  (Art.  Hcemorrhoidea  In- 
ferior Externa)  to  the  inferior  part  of  the  rectum,  and  to  the 

external  sphincter  ani  muscle.  This  artery  arises  after  the  inter- 
nal pudic  has  returned  within  the  pelvis,  and  consists  sometimes 
in  several  branches. 

c.  The  Perineal  Artery  (Art.  Perinea,  Transversa  Perinei)  has 
its  root  near  the  origin  of  the  transversus  perinei  muscle,  and 
advancing  obliquely  forwards  is  distributed  in  several  ramifica- 
tions to  the  muscles  and  integuments  of  the  perineum,  and  to  the 
posterior  part  of  the  scrotum.     It  is  unavoidably  cut  in  the  late- 
ral operation  for  the  stone.     In  the  female  it  goes  to  the  sphinc- 
ter vaginae  and  to  the  labium  externum. 

d.  When  the  internal  pudic  has  got  beyond  the  transversus 
perinei  muscle  near  the  beginning  of  the  crus  penis,  it  detaches 
to  the  bulb  of  the  urethra,  along  the  posterior  margin  of  the  tri- 
angular ligament,  a  branch  which  penetrates  to  the  corpus  spon- 
giosum,  and  is  minutely  distributed  upon  it,  some  of  its  ramifica- 
tions reaching  to  the  corpus  cavernosum.     This  branch  is  called, 
by  M.  Chaussier,  Urethro-bulbar,  and  instead  of  being  always 
distinct,  it  on  some  occasions  comes  from  the  Perineal. 

e.  At  the  under  part  of  the  symphysis  pubis,  between  it  and 
the  back  of  the  penis,  the  internal  pudic  sends  forwards,  on  the 
dorsum  of  the  penis,  a   superficial  branch,  (Ramus  Superficialis 
Dorsi  Pe?iis.)     It  advances  to  the  end  of  the  penis,  under  the 
skin,  being  parallel  with  its  fellow  of  the  other  side,  and  near  to 
it:  sometimes  the  two  unite  after  a  short  course.     They  are  dis- 
persed in  branches  to  the  integuments,  and  to  the  elastic  liga- 
ment of  the  penis. 

/.  The  Cavernous  Artery  of  the  Penis  (Art.  Cavernosa  Proftm- 
da  Pe?iis)  may  be  considered  as  the  terminating  trunk  of  the  in- 
ternal pudic.  It  penetrates  the  corpus  cavernosum,  beneath  the 
symphysis  of  the  pujbes,  and  quickly  divides  into  many  ramifica- 
tions. The  latter  advance,  and  continue  to  subdivide  upon  the 


236  CIRCULATORY  SYSTEM. 

cells  of  the  corpus  cavernosum,  to  which  they  are  principally 
distributed :  some  of  them  reach  the  corpus  spongiosum  urethrae, 
and  others  anastomose  with  the  corresponding  arteries  of  the 
other  side. 


SECT.    VIII. — OF  THE  EXTERNAL  ILIAC  ARTERY,  AND  ITS  BRANCHES. 

The  External  Iliac  Artery  (Arteria  lliaca  Externa)  extends 
from  the  bifurcation  of  the  primitive  iliac  to  Poupart's  ligament, 
where  it  is  continued  to  the  lower  extremity  under  the  name  of 
the  femoral  artery.  It  looks  like  the  continuation  of  the  primi- 
tive iliac,  and  descends  at  the  superior  strait  of  the  pelvis  along 
the  internal  margin  of  the  psoas  magnus  muscle.  In  the  early 
part  of  its  course,  it  is  anterior  to  the  external  iliac  vein ;  it  then, 
as  it  approaches  Poupart's  ligament,  gets  to  its  outer  margin. 
It  is  covered  by  the  peritoneum  in  front.  Where  it  passes  be- 
neath Poupart's  ligament  to  the  thigh,  it  is  about  half  way  be- 
tween the  anterior  superior  spinous  process  of  the  ilium  and  the 
symphysis  pubis,  having  the  vein  at  its  pubic  margin  and  the 
anterior  crural  nerve,  half  an  inch  from  its  iliac  margin.  No 
branches  of  consequence  arise  before  it  reaches  the  crural  arch ; 
it  then  sends  off  two,  the  Epigastric  and  the  Circumflex  of  the 
ilium. 

The  Epigastric  Artery  (Arteria  Epigastrica]  arises  somewhat 
above  the  crural  arch,  at  the  line  where  the  peritoneum  is  re- 
flected from  the  fascia  transversalis  upon  the  iliac  fascia.  It  at 
first  passes  horizontally  inwards,  then  rises  obliquely  upwards 
and  inwards,  behind  the  spermatic  chord,  at  the  pubic  margin 
of  the  internal  abdominal  ring.  Afterwards  it  reaches  the  ex- 
ternal margin  of  the  rectus  abdominis  muscle,  two  or  three 
inches  above  the  pubes :  ascending  along  it  for  a  short  distance, 
it  then  passes  to  its  posterior  face,  and  continues  ascending 
above  the  umbilicus ;  where  being  divided  into  several  branches, 
it  terminates  by  anastomosing  with  the  lower  ramifications  of 
the  internal  mammary  artery. 

This  artery  is  almost  entirely  spent  upon  the  anterior  parietes 
of  the  abdomen,  in  ramifications,  which  anastomose  with  the 
last  intercostal  and  with  the  lumbar  arteries.  One  of  its  small 


EXTERNAL  ILIAC  ARTERY,  AND  ITS  BRANCHES.  237 

twigs,  following  the  course  of  the  spermatic  chord,  or  of  the 
round  ligament,  is  distributed  upon  the  cremaster,  the  tunica 
vaginalis,  and  the  scrotum  of  the  male,  and  upon  the  mons  ve- 
neris  of  the  female.  In  some  cases  it  gives  off  the  obturator 
artery. 

The  Circumflex  Iliac  Artery  (Arteria  Circumfleoca  llii)  is  of  the 
same  size  with  the  epigastric,  and  comes  from  the  external  iliac, 
sometimes  on  a  level  with  it,  and  on  other  occasions  lower  down, 
even  below  the  crural  arch.  It  ascends  outwardly  towards  the 
anterior  superior  spinous  process  of  the  ilium,  along  the  posterior 
margin  of  the  crural  arch,  and  following  afterwards  the  direc- 
tion of  the  crista  of  the  ilium,  it  anastomoses  with  the  corre- 
sponding branch  of  the  ilio-lumbar  artery. 

The  following  branches  come  from  it.  In  the  early  part  of 
its  course  some  unimportant  twigs  are  sent  to  the  adjacent  mus- 
cles, as  the  sartorius,  iliacus  internus,  and  so  on.  At  the  ante- 
rior superior  spinous  process,  it  divides  into  two  branches,  the 
smaller  ascends  between  the  internal  oblique  and  the  transversa- 
lis  muscle,  and  is  distributed  upon  them;  the  other  branch, 
which  is  the  continuation  of  the  main  trunk  along  the  crista  of 
the  ilium  at  the  margin  of  the  iliacus  internus  muscle,  sends  ra- 
mifications to  the  latter,  and  also  to  the  posterior  part  of  the 
broad  muscles  of  the  abdomen,  where  it  anastomoses  with  the 
other  arteries  of  this  region. 

Of  the  Femoral  Artery. 

The  Femoral  Artery  (Arleria  Femoralis,  Cruralis]  the  continu- 
ation of  the  external  iliac,  extends  from  the  crural  arch  to  the 
perforation  for  its  passage  through  the  abductor  magnus,  which 
is  commonly  one-third  of  the  whole  length  of  the  os  femoris, 
above  the  knee  joint.  This  great  trunk,  immediately  below 
Poupart's  ligament  is  very  superficial,  and  may  be  felt  pulsating 
where  it  passes  over  the  pubes.  It  is  there  covered  only  by  the 
common  integuments  and  the  fascia  femoris,  which  is  thin ;  it  is 
bounded  internally  by  the  femoral  vein,  externally  by  the  crural 
nerve,  is  half-way  between  the  anterior  superior  spinous  process 
and  the  symphysis  of  the  pubes,  and  lies  upon  the  internal  face 
VOL.  IL— 31 


238  CIRCULATORY  SYSTEM. 

of  the  psoas  magnus  over  the  interstice  between  it  and  the  pec- 
tineus.  In  the  upper  third  of  its  course  the  femoral  artery  is  at 
the  inner  edge  of  the  rectus  femoris,  and  at  a  short  distance  from 
it ;  it  then  inclines  inwards,  and  occupies  the  angle  formed  by 
the  adhesion  of  the  vastus  internus  to  the  adductor  longus.  The 
sartorius,  at  first,  is  remote  at  its  outside,  but  this  muscle  inclining 
inwards  in  its  descent  gets  to  the  exterior  margin  of  the  artery, 
and  afterwards  covers  it  completely  for  the  remainder  of  its 
course.  The  femoral  artery  is  in  front  of  the  femoral  vein  when 
it  has  descended  tliree  or  four  inches  below  the  crural  arch :  be- 
hind the  two  is  the  arteria  profunda.  When  the  femoral  artery 
and  vein  reach  the  angle  formed  by  the  vastus  internus  and  the 
adductor  longus,  they  are  covered  by  a  strong  interlacement  of 
tendinous  fibres  from  these  muscles. 

The  femoral  artery  sends  off  these  branches: — 

1.  The  Superficial  Artery  of  the  Abdomen  (Art.  ad  Cutem  Ab- 
dominis)  is  small,  and  arises  at  the  lower  margin  of  Poupart's 
ligament ;  it  goes  upwards  towards  the  umbilicus,  lies  beneath 
the  fascia  superficialis  abdominis,  and  is  distributed  to  the  in- 
teguments of  this  region.     One  of  its  ramifications  goes  to  the 
inguinal  glands. 

2.  The  External  Pudic  Arteries  (Art.  Pudenda  External)  come 
from  the  femoral  at  the  same  point,  and  are  two  or  even  three 
in  number ;  they  are  of  small  size.     One  of  them  inclines  inwards 
along  the  groin,  between  the  skin  and  the  fascia  femoris,  and  is 
distributed  to  the  integuments  of  the  pubes — to  those  of  the 
penis, — and  to  the  scrotum,  or  to  the  labium  externum  of  the  fe- 
male.    The  second,  and  the  third  when  it  exists,  are  rather 
lower  down,  and  are  dispersed  upon  very  much  the  same  parts. 
The  lymphatic  glands  of  the  groin  also  derive  their  supply  of 
blood  from  these  external  pudic  arteries. 

3.  The  Profound  Artery,  (Arteria  Profunda  Femoris,}  the  great 
muscular  artery  of  the  thigh,  is  but  slightly  inferior  in  size  to  the 
femoral  itself,  and  comes  from  the  latter  at  the  distance  of  from 
one  to  two  inches  below  the  crural  arch.     It  lies  behind  the  fe- 
moral artery,  and  descends  in  that  situation  between  the  inser- 


EXTERNAL  ILIAC  ARTERY,  AND  ITS  BRANCHES.  239 

tion  of  the  adductor  brevis  and  the  vastus  interims  muscle,  to 
the  upper  part  of  the  insertion  of  the  adductor  longus.  In  this 
course,  its  size  is  much  diminished,  by  the  origin  from  it  of  seve- 
ral considerable  trunks,  as  follows : — 

a.  The  External  Circumflex,  (Arteria  Circumflexa  External) 
though  most  frequently  a  branch  of  the  profunda,  sometimes 
comes  from  the  femoral  above  or  below  it  a  short  distance.  It 
goes  immediately  outwards  between  the  rectus  femoris  muscle 
and  the  cruralis,  giving  off  some  inconsiderable  ramifications. 
While  between  these  muscles  it  divides  into  two  branches,  one 
of  which  ascends,  and  the  other  descends;  the  former  is  distri- 
buted to  the  anterior  margins  of  the  gluteus  medius  and  minimus, 
to  the  capsule  of  the  joint,  and  the  parts  about  the  trochanter 
major,  anastomosing  with  the  gluteal  and  the  ischiatic.  It  is 
said  by  Meckel,  that  these  anastomoses  have  been  found  much 
dilated  where  the  external  iliac  artery  has  been  taken  up.  The 
descending  branch  is  about  the  size  of  a  crow  quill,  or  even 
larger ;  it  first  passes  obliquely  downwards  between  the  rectus 
femoris  and  the  cruralis,  it  then  descends  vertically  under  the 
anterior  margin  of  the  vastus  externus,  between  it  and  the  cru- 
ralis, to  terminate  at  the  knee,  where  it  becomes  superficial  and 
anastomoses  with  the  articular  arteries.  It  is,  however,  princi- 
pally distributed  to  the  vastus  externus  and  to  the  cruralis. 

6.  The  Internal  Circumflex  Artery  (Arteria  Circumflexa  In- 
terna)  arises  from  the  profunda,  near  the  external  circum- 
flex, generally  below  it,  but  sometimes  the  reverse;  in  some 
cases,  it  comes  from  the  femoral  artery  itself,  near  the  crural 
arch.  It  passes  transversely  inwards,  and  dips  into  the  inter- 
stice between  the  pectineus  and  the  psoas  magnus,  after  having 
given  off  some  small  twigs  to  the  heads  of  the  adjoining  ad- 
ductors. It  then  winds  under  the  neck  of  the  os  femoris  and 
divides  into  two  branches;  the  upper  one  goes  to  the  capsular 
ligament  of  the  joint,  to  the  obturator  externus  muscle,  anasto- 
moses with  the  obturator  artery,  and  sends  a  branch  behind  the 
adductor  brevis  to  the  upper  part  of  the  adductor  magnus :  the 
inferior  branch  is  larger  than  the  other ;  it  descends  behind  the 
adductor  magnus  and  is  distributed  in  branches  to  it,  to  the  gra- 
cilis,  and  to  the  hamstring  muscles,  sending  upwards  some  rami- 
fications (raini  trochanterici]  to  the  parts  about  the  trochanter 


240  CIRCULATORY  SYSTEM. 

major,  where  they  anastomose  with  the  external  circumflex  ar- 
tery. 

c.  Muscular  branches  of  inconstant  origin,  and  of  inconsider- 
able size,  are  sent  from  the  profunda  to  supply  the  anterior  face 
of  the  adductor  muscles. 

d.  The  Perforating  Arteries  (Rami  Profundi  Perforantes)  ob- 
tain the  name  from  their  perforating  the  adductor  magnus,  which 
they  do  near  the  linea  aspera,  so  as  to  get  to  the  back  of  the 
thigh.     They  commonly  are  four  in  number,  and  as  they  come 
off  successively  from  the  profunda,  they  are  designated  numeri- 
cally.    In  some  cases,  however,  they  are  reduced  to  one,  by  be- 
ing concentrated  in  a  common  trunk,  which,  penetrating  high  up 
the  adductor  magnus,  and  afterwards  descending  on  its  posterior 
face,  is  dispersed  upon  the  muscles  on  the  back  of  the*  thigh. 

The  First  Perforating  Artery  arises  somewhat  below  the  tro- 
chanter  minor,  and  penetrates  the  adductor  magnus  a  little  be- 
low its  superior  margin.  One  of  its  branches  ascends  towards 
the  trochanter  major,  where  it  anastomoses  with  the  external 
circumflex  and  with  the  gluteal,  while  another  descending  is 
spent  upon  the  heads  of  the  flexor  muscles  of  the  leg. 

The  Second  Perforating  Artery  gets  to  the  back  of  the  thigh, 
at  the  lower  margin  of  the  insertion  of  the  gluteus  maximus  into 
the  linea  aspera,  being  distributed  in  that  region,  and  to  the  cor- 
responding portion  of  the  long  head  of  the  biceps  flexor  cruris. 

The  Third  Perforating  Artery  penetrates  the  Adductor  mag- 
nus somewhat  below  the  commencement  of  the  short  head  of 
the  biceps,  and  is  dispersed  upon  the  adductor  and  the  adjacent 
portion  of  the  flexor  muscles. 

The  Fourth  Perforating  Artery  penetrates  the  insertion  of  the 
adductor  magnus  an  inch  and  a  half  above  the  opening  in  it,  for 
the  femoral  artery ;  it,  in  the  same  way,  supplies  the  posterior 
face  of  the  adductor  and  the  adjacent  muscles. 

As  a  summary,  it  will  be  readily  understood  that  the  profunda 
is,  in  this  way,  through  the  external  and  the  internal  circumflex, 
and  through  the  perforating  arteries,  distributed  upon  all  the 
large  muscles  of  the  thigh. 

After  the  origin  of  the  profunda,  the  Femoral  Artery  gives 


POPLITEAL  ARTERY,  AND  ITS  BRANCHES.  241 

off,  at  different  points  of  its  course  to  the  opening  of  the  ad- 
ductor magnus ;  several  twigs  the  size  of  a  large  knitting  needle, 
which  go  to  the  sartorius,  the  gracilis,  the  adductors,  and  the 
extensors  on  the  front  of  the  thigh ;  but  they  are  too  inconstant 
to  require  more  particular  description. 

The  Anastomosing  Artery  (Arteria  Anastomotica)  is  the  last 
branch  of  the  femoral,  and  arises  just  before  it  perforates  the 
adductor  magnus.  It  descends  to  the  knee,  in  front  of  the  ten- 
don of  the  latter,  concealed  by  the  internal  margins  of  the  vastus 
internus  muscle.  It  sends  off  many  small  twigs  to  the  adjacent 
muscles,  and  terminates  below  by  anastomosing  with  the  inter- 
nal articular  arteries.  It  is  about  the  size  of  a  crow-quill. 

The  Popliteal  Artery  (Arteria  Poplitcea)  is  the  continuation  of 
the  femoral,  after  the  latter  has  passed  through  the  tendinous 
insertion  of  the  adductor  magnus,  and  extends  from  this  point  to 
the  opening  in  the  interosseous  ligament  of  the  leg,  just  below 
the  head  of  the  tibia.  It,  first  of  all,  passes  from  the  internal 
margin  of  the  os  femoris,  to  the  notch  between  the  condyles; 
being  there  placed  in  the  middle  between  the  internal  and  the 
external  hamstring  muscles,  and  surrounded  by  a  mass  of  adi- 
pose matter  which  fills  up  the  hollow  of  the  ham.  It  is  in  con- 
.tact,  anteriorly,  with  the  knee  joint,  and  a  little  below  the  latter 
with  the  popliteus  muscle,  descending  there  between  the  heads 
of  the  gastrocnemius.  It  is  covered,  in  the  greater  part  of  its 
extent,  posteriorly,  by  the  popliteal  vein,  and  by  the  sciatic  nerve, 
the  latter  being  more  superficial  than  the  vein. 

The  popliteal  artery  sends  off  some  small  branches  to  the 
hamstring  muscles,  and  to  the  parts  contained  between  the  lat- 
ter, which  are  too  irregular  and  inconstant  for  description.  The 
following  arteries,  also,  come  from  it: — 

1.  The  Superior  Internal  Articular  Artery  (Jlrt.  JLrticularis 
Superior  Internet)  arises  at  or  above  the  internal  condyle,  and 
frequently  consists  in  two  trunks.  It  passes  through  the  ten- 
don of  the  adductor  magnus,  just  above  the  condyle;  it  then  be- 
gins to  distribute  itself  in  branches,  some  of  which  are  spent 


242  CIRCULATORY  SYSTEM. 

upon  the  lower  part  of  the  vastus  internus  muscle,  and  others 
upon  the  superior  internal  part  of  the  knee  joint. 

2.  The  Superior  External  Articulating  Artery  (*ftrl.  Articu- 
laris  Superior  Externa]  arises  from  the  popliteal,  somewhat 
above  the  external  condyle  of  the  os  femoris.     It  winds,  hori- 
zontally, above  the  external  condyle,  around  the  bone,  between 
it  and  the  lower  part  of  the  biceps  flexor  cruris,  and  is  then  dis- 
tributed, also,  in  two  orders  of  branches,  some  of  which  supply 
the  lower  part  of  the  vastus  externus  muscle,  and  others  the 
superior  external  portion  of  the  knee  joint. 

3.  The  Middle  Articular  Artery  (*flrt.  Articularis  Media) 
is  smaller  than  either  of  the  above,  and  sometimes  comes  from 
one  of  them,  but  generally  from  the  popliteal,  on  a  line  with 
the  articulation  of  the  knee.     It  is  distributed  to  the  posterior 
part  of  the  capsular  ligament,  to  the  crucial  ligaments,  and  to 
the  corresponding  adipose  matter. 

4.  The  Inferior  Internal  Articular  Artery  (Art.  Articularis  In- 
ferior Interna)  arises  on  a  line  with  the  inferior  part  of  the  inter- 
rial  condyle,  sometimes  lower  down.     Its  origin  is  very  much 
concealed  by  the  internal  head  of  the  gastrocnemius;  it  passes 
beneath  the  latter,  and   then  between  the  internal  lateral  liga- 
ment of  the  knee  and  the  head  of  the  tibia;  consequently,  it  is 
covered  by  the  internal  hamstring  muscles.     It  afterwards  as- 
cends  towards   the   patella,   and    is   distributed    in    numerous 
branches  to  the  inferior  internal  part  of  the  knee  joint,  and  to 
the  adjacent  portion  of  the  tibia. 

5.  The  Inferior  External  Articular  Artery   (Art.  Articularis 
Inferior  Externa)  arises  near  the  last,  below  the  external  condyle, 
being  concealed  by  the  belly  of  the  plantaris.     It  passes,  hori- 
zontally, or  nearly  so,  between  the  popliteus  and  the  outer  head 
of  the  gastrocnemius,  and  afterwards  beneath  the  tendon  of  the 
biceps  and  the  external  lateral  ligament  of  the  joint,  around  the 
external  face  of  the  head  of  the  tibia.     It  gives  small  branches 
to  these  several  parts,  and  is  then  distributed,  by  two  orders  of 


EXTERNAL  ILIAC  ARTERY,  AND  ITS  BRANCHES.  243 

ramifications,  to  the  superficial  and  to  the  more  deeply  seated 
parts  at  the  external  inferior  portion  of  the  knee  joint. 

These  several  articular  arteries  anastomose  freely  with  each 
other,  and  are  minutely  ramified  on  the  knee  joint  and  the  con- 
tiguous structure.  They  also  anastomose  with  the  long  de- 
secnding  branch  of  the  external  circumflex  of  the  thigh,  with 
the  ananstomotica  of  the  femoral,  and  with  the  tibial  recurrent. 

6.  The  Gastrocnemial  Arteries  (Arterial  Gemellce)  are  two  in 
number,  one  for  each  head  of  the  gastrocnemius.  They  arise 
commonly  between  the  superior  and  the  inferior  articular  arte- 
ries, and  are  about  the  same  size.  They  penetrate  into  the 
muscle,  and  supply  it  with  blood,  terminating  their  course  near 
the  lower  part  of  its  bellies. 

Moreover,  some  small  branches,  which  go  to  the  contiguous 
muscles,  are  frequently  observed  here;  also,  the  nutritious  ar- 
tery of  the  tibia.  But  their  number  and  condition  are  very  in- 
constant. Near  the  head  of  the  fibula,  branches  go  from  the 
popliteal  artery  to  the  upper  end  of  the  soleus  muscle. 

Generally,  on  a  level  with  the  aperture  in  the  upper  part  of 
the  interosseous  ligament,  but  sometimes  an  inch  or  two  higher 
up,  the  popliteal  artery  terminates  by  dividing  into  two  large 
trunks,  the  Anterior  and  the  posterior  Tibial. 

The  Anterior  Tibial  Artery  (Art.  Tibialis  interior]  passes 
forwards  through  the  foramen  of  the  interosseous  ligament,  just 
below  the  head  of  the  fibula,  and  runs  down  the  front  of  the  leg 
and  foot,  as  far  as  the  base  of  the  metatarsal  bone  of  the  great 
toe.  In  this  course,  its  relative  situation  is  as  follows:  It  rests 
upon  the  front  of  the  interosseous  ligament  of  the  leg,  on  a  line 
drawn  from  the  middle  anterior  part  of  the  head  of  the  fibula 
to  the  middle  of  the  ankle  joint.  Superiorly,  it  is  bounded  on 
the  tibial  side  by  the  tibialis  anticus  muscle,  and  on  the  other 
by  the  extensor  longus  digitorum:  lower  down  on  the  leg,  the 
place  of  the  latter  is  supplied  by  the  extensor  pollicis  pedis. 
Somewhat  above  the  ankle  joint  the  artery,  leaving  the  inter- 
osseous ligament,  rests  upon  the  front  of  the  tibia,  and  then  gets 
to  the  top  of  the  foot,  between  the  joint  and  the  annular  liga- 


244  CIRCULATORY  SYSTEM. 

ment.  Under  the  ligament  it  is  crossed  by  the  tendon  of  the 
extensor  pollicis,  which  gets  to  its  inner  side,  and  afterwards 
continues  so.  The  anterior  tibial  nerve  adheres  to  it,  in  its 
whole  length. 

The  following  branches  come  from  the  anterior  tibial  ar- 
tery:— 

1.  The  Recurrent  Tibial  (<flrt.  Tibialis  Recurrens)  ascends 
through  the  upper  extremity  of  the  tibialis  anticus  muscle,  having 
come  off  from  the  anterior  tibial  immediately  upon  the  latter 
getting  to  the  front  of  the  leg.     Several  small  ramifications  pass 
from  it  to  the  heads  of  the  contiguous  muscles  on  the  tibia,  and 
to  the  lower  part  of  the  knee  joint,  where  it  anastomoses  with 
the  lower  articular  arteries  of  the  knee. 

2.  Several  small  arterial  twigs  are  afterwards  sent  to  the 
muscles  and  to  the  periosteum  of  the  leg,  as  the  anterior  tibial 
descends,  but  they  are  too  inconstant  in  size  and  position  to  re- 
quire description. 

3.  The  Internal  Malleolar  Artery  (Art.  Malleolaris  Internet) 
arises  from  the  anterior  tibial,  an  inch  or  two  above  the  ankle 
joint.     It  descends,  inwardly,  between  the  tibia  and  the  tendon 
of  the  tibialis  anticus,  and,  having  gained  the  internal  malleolus, 
is  distributed  by  branches  upon  it  and  upon  the  adjacent  portion 
of  the  articulation. 

4.  The  External  Malleolar  Artery  (Art.  Malleolaris  Externa) 
consists  most  commonly  in  two  arterial  twigs  of  small  size,  but 
frequently  in  one  only.     It  arises  in  front  of  the  ankle  joint, 
and  going  outwardly  between  it  and  the  tendons  of  the  extensor 
digitorum  longus,  is  spent  upon  the  external  face  of  the  articu- 
lation, where  it  inosculates  with  the  peroneal  artery. 

This  artery  is  sometimes  of  considerable  size,  in  which  case 
it  also  supplies  the  outer  part  of  the  tarsus,  and  is  a  substitute 
for  the  next. 

5*  The  Tarsal  Artery  (Arteria  Tarsea)  arises  from  the  anterior 
tibial,  somewhat  below  the  ankle  joint  near  the  scaphoides,  and, 


EXTERNAL  ILIAC  ARTERY,  AND  ITS  BRANCHES.  245 

going  outwardly  beneath  the  extensor  brevis  digitorum  muscle, 
it  is  distributed  in  branches  near  the  external  ankle,  and  upon 
the  outer  upper  surface  of  the  tarsus.  It  anastomoses  with  the 
external  malleolar,  with  the  external  plantar,  and  with  the  me- 
tatarsal  artery. 

Some'small  branches  also  pass  from  the  anterior  tibial  at  this 
point  to  the  upper  internal  face  of  the  tarsus. 

6.  The  Metatarsal  Artery  (*2rt.  Metatarsea)  arises  just  be- 
low the  last.     It  is  directed  forwards  and  outwards  beneath  the 
extensor  brevis  muscle,  and  forms  a  sort  of  arch  at  the  roots  of 
the  metatarsal  bones.     It  furnishes  several  ramifications  to  the 
upper  surface  of  the  tarsus  and  the  contiguous  parts;  amongst 
them  is  an  interosseal  artery  for  each  of  the  three  outer  interos- 
seal  spaces.     These  arteries  communicate,  by  small  anastomoses, 
with  the  arteries  of  the  sole  of  the  foot,  both  at  the  bases  and  at 
the  ends  of  the  metatarsal  bones,  and  terminate  in  front  by  sup- 
plying the  backs  of  the  small  toes. 

This  artery  is  sometimes  a  branch  of  the  tarsal. 

7.  The  Dorsal  Artery  of  the  Great  Toe  (Art.  Dorsalis  Hal- 
lucis)  arises  from  the  anterior  tibial  at  the  root  of  the  first  me- 
tatarsal bone.     It  runs  along  the  superior  face  of  the  first  me- 
tatarsal interval,  and,  having  reached  the  anterior  end  of  it,  di- 
vides into  two  branches,  one  of  which  goes  to  the  back  of  the 
great  toe  and  the  other  to  the  tibial  margin  of  the  next  toe. 

The  Anterior  Tibial,  in  its  course  from  the  ankle  joint  to  the 
base  of  the  first  metatarsal  bone,  is  sometimes  called  Pedal  («#r- 
teria  Pedicea;}  at  the  posterior  end  of  the  first  metatarsal  inter- 
val, being  still  of  considerable  size,  it  sinks  down  to  the  sole 
of  the  foot,  and  joins  itself  to  the  external  plantar  artery  at  this 
point. 

It  frequently  happens  that  the  anterior  tibial  being  small  in 
its  course  down  the  leg,  is  joined  by  the  continued  trunk  of  the 
peroneal,  which  perforates  the  interosseous  ligament  somewhat 
above  the  ankle  joint.  Afterwards  the  trunk  formed  by  this 
union,  being  of  considerable  size,  follows  the  course  and  has  the 
distribution  mentioned. 
VOL.  II.— 32 


246  CIRCULATORY  SYSTEM. 

The  Posterior  Tibial  Artery  (Arteria  Tibialis  Posticti)  is 
sometimes  called,  at  its  commencement,  till  it  gives  off  the  pe- 
roneal, tibio-peroneal;  it  extends  from  the  head  of  the  tibia  to 
the  sinuosity  of  the  os  calcis,  in  a  line  from  the  middle  of  the 
ham  to  the  internal  ankle.  It  is  at  the  tibial  side  of  the  back  of 
the  leg,  on  the  posterior  face  of  the  flexor  longus  digitorum  mus- 
cle; and  covered  by  the  fascia  of  the  latter.  In  the  two  supe- 
rior thirds  of  its  course,  it  is  concealed  behind  by  the  gastroc- 
nemius  and  the  solaeus  muscle:  in  the  inferior  third,  it  is  at  the 
internal  margin  of  the  tendo-achillis.  At  the  ankle  joint,  be- 
fore it  passes  into  the  sinuosity  of  the  os  calcis,  it  is  between 
the  tendon  of  the  tibialis  posticus  and  that  of  the  flexor  lon- 
gus pollicis  pedis,  being  covered  by  the  laciniated  ligament.  It 
is  accompanied,  at  its  external  margin,  by  the  posterior  tibial 
nerve. 

The  posterior  tibial  artery  is  distributed  after  the  following 
manner: — 

1.  The  Peroneal  Artery  (Jlrteria  Peronea]  is  its  first  branch 
of  any  importance,  and  is  but  little  smaller  than  the  continued 
trunk.  It  arises  an  inch  or  two  below  the  origin  of  the  ante- 
rior tibial,  and  extends,  on  the  posterior  face  of  the  leg,  to  the 
external  ankle.  It  is,  in  some  measure,  concealed  by  the  pos- 
terior side  of  the  fibula,  being  placed  there  between  the  origin 
of  the  flexor  longus  pollicis  muscle  and  the  external  edge  of  the 
tibialis  posticus.  It  is  covered  behind  by  the  flexor  longus  pol- 
licis, by  the  soleus,  and  by  the  gastrocnemius;  it  is,  therefore, 
deep  and  of  extremely  difficult  access  in  the  living  body. 

In  this  course,  it  sends  small  branches  to  the  gastrocnemius, 
to  the  soleus,  and  to  the  other  contiguous  muscles  on  the  back 
of  the  leg.  After  having  descended  two-thirds  of  the  length  of 
the  fibula,  it  divides  into  an  anterior  and  a  posterior  branch. 
The  former  traverses  the  interosseous  ligament,  and,  descend- 
ing in  front  of  it,  covered  by  the  muscles  which  arise  from  the 
lower  part  of  the  fibula,  is  distributed  upon  the  upper  external 
part  of  the  foot  near  the  ankle  joint.  The  posterior  branch  con- 
tinues in  the  primitive  course  of  the  peroneal  artery  at  the  in- 
ternal posterior  margin  of  the  fibula,  and  descending  behind  the 
tibio-peroneal  articulation,  reaches  the  external  face  of  the  os 


EXTERNAL  ILIAC  ARTERY,  AND  ITS  BRANCHES.     247 

calcis;  it  detaches  several  small  ramifications  to  the  contiguous 
muscles;  and,  upon  the  os  calcis,  is  divided  into  twigs  which 
supply  the  adjacent  parts  and  the  integuments  below  the  exter- 
nal ankle. 

2.  In  the  descent  of  the  posterior  tibial  artery  to  the  hollow 
of  the  os  calcis,  it  detaches  several  small  muscular  branches, 
principally  to  the  tibialis  posticus,  and  to  the  flexors  of  the  toes. 
One  twig,  which  is  the  nutritious  artery  of  the  tibia,  comes  from 
its  upper  part  when  not  furnished  from  the  popliteal  artery,  and 
enters  the  foramen  on  the  posterior  surface  of  the  bone. 

While  the  posterior  tibial  is  in  the  hollow  of  the  os  calcis, 
between  it  and  the  abductor  muscle  of  the  great  toe,  it  furnishes 
some  small  twigs  to  the  contiguous  muscles,  and  to  the  integu- 
ments of  the  sole  of  the  foot;  it  then  divides  into  two  branches, 
the  Internal  and  the  External  Plantar  Artery. 

The  Internal  Plantar  Artery  (Jlrt.  Plantaris  Interna)  is 
much  smaller  than  the  other.  It  advances  between  the  abductor 
pollicis  pedis  and  the  internal  inferior  margin  of  the  sole  of  the 
foot,  and  terminates  at  the  anterior  end  of  the  first  metatarsal 
bone,  by  joining  the  internal  digital  artery  of  the  great  toe.  In 
this  course,  it  sends,  continually,  small  ramifications  to  the  mus- 
cles of  the  great  toe  and  to  the  flexor  brevis  digitorum  pedis. 
One  of  the  largest  of  these  ramifications  comes  off  near  the  os 
scaphoides,  and  cruises  along  the  internal  margin  of  the  abduc- 
tor pollicis  to  its  anterior  end;  another  becomes  superficial  on 
the  sole  of  the  foot,  between  the  abductor  pollicis  and  the  flexor 
brevis,  and  goes  forward  as  far  as  the  other. 

The  External  Plantar  Artery  (Jlrt.  Plantaris  Externa]  is 
the  continuation  of  the  posterior  tibial,  and  diverges  from  the 
internal  plantar  towards  the  outer  margin  of  the  sole  of  the  foot, 
between  the  flexor  brevis  digitorum  pedis  and  the  flexor  acces- 
sorius.  Having  reached  the  internal  margin  of  the  abductor 
minimi  digiti,  it  advances  along  the  latter  to  the  base  of  the  me- 
tatarsal bone  of  the  fourth  toe;  it  then  makes  a  curvature  for- 
wards and  inwards,  across  the  metatarsal  bones,  between  the  ten- 


248  CIRCULATORY  SYSTEM. 

dons  of  the  flexor  longus  and  the  inter  osseous  muscles,  to  the  first 
metatarsal  interval,  where  it  is  joined  by  the  anterior  tibial  ar- 
tery from  above.  This  curvature  is  the  Arc  us  Plantaris,  of 
which  the  concavity  is  behind  and  inwards. 

The  external  plantar  artery  is  distributed  as  follows : — 
Shortly  after  its  origin,  it  detaches  a  branch  which  goes  back- 
wards and  outwards,  and  which,  keeping  close  to  the  os  calcis 
in  front  of  its  tuberosity,  is  distributed  to  the  heads  of  the  mus- 
cles arising  from  it,  and  to  the  outer  surface  of  the  heel ;  it  "also 
sends  an  arteriole  along  the  external  edge  of  the  abductor  mini- 
mi digiti. 

At  the  base  of  the  fourth  metatarsal  bone,  arises  a  branch 
called  the  External  Digital  Artery  of  the  Little  Toe.  It  goes  at 
first  deeply  along  the  internal  margin  of  the  muscles  situated  on 
the  fifth  metatarsal  bone,  and,  afterwards,  at  the  head  of  the  lat- 
ter, it  gets  between  them  and  the  bone,  and  is  distributed  along 
the  external  margin  of  the  little  toe. 

The  four  Digital  Arteries  of  the  foot  arise  next  successively 
from  the  arcus  plantaris,  at  or  near  the  metatarsal  intervals. 
They  run  along  the  inferior  surface  of  the  interosseous  muscles, 
getting  to  the  bases  of  the  first  phalanges  above  the  transversalis 
pedis.  Each  artery  there  bifurcates,  so  as  to  supply  the  opposed 
surfaces  of  the  adjacent  toes,  in  the  same  way  that  the  digital 
arteries  of  the  hand  are  distributed. 

The  digital  artery  of  the  first  metatarsal  interval  which  comes 
from  the  internal  extremity  of  the  arcus  plantaris,  where  the  an- 
terior tibial  artery  joins  the  latter,  goes  forwards  concealed  by 
the  flexor  brevis  of  the  great  toe :  just  behind  the  sesamoid  bones, 
it  sends  a  branch  which  supplies  the  internal  side  of  the  great 
toe,  being  its  internal  digital  artery,  and  anastomoses  with  the 
internal  plantar  artery.  What  remains  of  it,  is  still  a  trunk  of 
considerable  magnitude,  which  advancing  to  the  space  between 
the  first  phalanx  of  the  great  toe  and  of  the  toe  next  to  it,  there 
bifurcates,  as  mentioned,  so  as  to  supply  the  opposite  sides  of 
these  two  toes. 

The  Perforating  Arteries,  as  they  are  called,  are  of  two  kinds, 


OF  THE  VEINS.  249 

the  anterior  and  the  posterior.  The  former  arise  from  the  con- 
vexity of  the  plantar  arch,  and  being  destined  principally  to  the 
interosseous  muscles,  anastomose  at  the  anterior  end  of  the  lat- 
ter with  the  branches  from  the  metatarsal  artery,  which  supply 
their  superior  surface.  The  posterior  perforating  arteries  come 
also  from  the  plantar  arch,  and  penetrating  the  posterior  end  of 
the  interosseous  spaces,  anastomose  also  with  the  metatarsal  ar- 
teries on  the  dorsum  of  the  foot. 

The  preceding  trunks  of  the  internal  and  of  the  external  plan- 
tar arteries  are  the  principal  ones  which  are  found  in  the  bottom 
of  the  foot,  but  from  them  there  arise  an  immense  number  of  ar- 
terioles ;  which,  descending  vertically  between  the  interstices  of 
the  muscles  and  of  the  aponeurosis  plantaris,  supply  the  adipose 
matter  and  the  skin  of  the  sole  of  the  foot,  so  as  to  render  them 
extremely  vascular. 


CHAPTER  III. 

OF  THE  VEINS. 

THE  veins  of  the  body,  assembling  from  different  points,  unite 
successively  into  the  ascending  and  into  the  descending  vena 
cava,  which  discharge  their  blood  into  the  right  auricle  of  the 
heart.  The  veins  of  the  head,  of  the  upper  extremities,  and  of 
the  thorax,  run  into  the  descending  cava,  while  the  veins  of  the 
abdomen  and  of  the  lower  extremities  concur  to  form  the 
ascending  cava. 

SECT.  I. — OF  THE  VEINS  OF  THE  HEAD  AND  NECK, 

Many  of  these  veins  are  described  elsewhere  with  the  en- 
cephalon  and  with  the  eye,  to  which  account  the  reader  is  re- 
ferred. The  others  are  more  superficial,  and  arise  as  follows: — 

^  The  Facial  Vein*  ( Vena  Facialis)  observes  the  course  of  the 


250  CIRCULATORY  SYSTEM, 

facial  artery,  being  placed  behind  the  latter.  It  arises  upon  the 
forehead  by  a  considerable  number  of  roots,  which  unite  into  a 
single  trunk  called  the  frontal  vein.  This  vein  descends  from 
the  forehead,  over  the  root  of  the  nose,  along  the  internal  can- 
thus  of  the  orbit.  It  there  receives  re-enforcements  from  the 
eyelids,  and  anastomoses  with  the  ophthalmic  veins ;  descending 
afterwards,  in  the  same  way  with  the  facial  artery,  and  taking 
the  name  of  facial  vein,  it  receives  successively  the  veins  from 
the  nose,  from  the  outer  side  of  the  orbicularis  palpebrarum,  from 
the  upper  and  lower  lips,  and  from  the  muscles  and  the  inte- 
guments of  the  face.  It  descends  to  the  neck  at  the  anterior 
margin  of  the  masseter  muscle,  and  is  then  augmented  by  the 
ranine,  the  submental,  and  the  inferior  palatine  veins,  and  im- 
mediately afterwards  goes  into  the  internal  or  the  external  ju- 
gular vein. 

The  Ranine  Vein  ( Vena  Ranina)  arises  at  the  point  of  the 
tongue,  and  then  goes  along  its  under  surface,  where  it  can 
be  readily  seen  by  turning  up  the  end  of  the  tongue.  It  joins 
the  facial  near  the  posterior  margin  of  the  mylo-hyoideus  mus- 
cle. 

The  Submental  Vein  ( Vena  Submentalis)  arises  by  ramuscles 
from  the  sublingual  and  submaxillary  glands,  and  from  the  con- 
tiguous muscles.  It  joins  the  facial  vein  a  little  below  the  last : 
sometimes  it  runs  into  the  superior  thyroidal  vein. 

The  Inferior  Palatine  Vein  (Vena  Palatina  Inferior]  arises 
principally  from  the  soft  palate  and  from  the  tonsil  gland,  but 
receives  a  few  twigs  from  the  contiguous  parts.  It  corresponds 
with  the  inferior  palatine  artery,  a  branch  of  the  lingual ;  and 
descends  the  pharynx  alongside  of  it,  and  terminates  in  the 
trunk  of  the  facial  near  the  last. 

The  Lingual  Vein  (Vena  Lingualis]  has  its  origin  from  a 
plexus  of  veins  situated  on  the  root  of  the  tongue  under  its  lining 
merribrane,  between  the  epiglottis  and  the  foramen  caecum: 
branches  are  also  sent  to  it  from  the  muscular  structure  of  the 
tongue,  from  the  sublingual  gland  and  from  the  adjacent  mus- 


VEINS  OF  THE  HEAD  AND  NECK.  251 

cles.  and  it  anastomoses  with  the  vena  ranina.  It  goes  back- 
wards between  the  hyo-glossus  and  the  mylo-hyoideus  muscle, 
along  the  superior  margin  of  the  os  hyoideus,  and  then  dis- 
charges into  the  internal  jugular  vein  near  the  facial. 

The  Pharyngeal  Vein  ( Vena  Pharynged)  arises  from  a  plexus 
of  veins  belonging  to  the  pharynx,  and  discharges  either  into 
the  lingual  or  into  the  internal  jugular  near  it. 

The  Superior  Thyroid  Vein  (Vena  Thyroidea  Superior]  cor- 
responds with  the  distribution  of  the  superior  thyroid  artery, 
in  the  origin  of  its  primitive  roots.  Having  collected  the  lat- 
ter into  one  or  more  trunks,  it  passes  upwards  and  backwards 
beneath  the  sterno-hyoid  and  thyroid  muscles,  and  discharges 
itself  into  the  upper  part  of  the  internal  jugular,  or  into  one  of 
the  large  branches  of  the  external  jugular. 

The  Occipital  Vein  (Vena  Occipitalis)  arises  from  the  branches 
of  the  occipital  artery,  and  following  the  course  of  the  latter, 
beneath  the  muscles  connected  with  the  mastoid  process  of  the 
temporal  bone,  it  is  discharged  into  the  upper  part  of  the  inter- 
nal jugular  or  of  the  external;  more  rarely  into  the  latter. 

The  Diploic  Veins  (Vena  Diploicce)  have  been  described  in 
the  account  of  the  bones  of  the  cranium  as  situated  between  the 
two  tables  in  the  diploic  structure,  and  commence  by  very  fine 
capillary  tubes  from  its  lining  membrane.  The  one  in  the  fron- 
tal bone  discharges  itself  into  the  frontal  vein,  that  in  the  occi- 
pital bone  into  the  occipital  vein,  and  the  two  in  the  parietal 
bone  into  the  deep  temporal  veins.  They  do  not  open  each  by 
one  orifice,  but  by  several,  which  makes  their  termination  not 
very  distinct  or  abrupt:  besides  which,  they  communicate  free- 
ly by  a  crowd  of  raniuscles,  with  the  veins  of  the  scalp  on  the 
outside,  and  with  those  of  the  dura  mater  internally. 


i 

dii 


The  Superficial  Temporal  Vein  (Vena  Temporalis  Superfi- 
cialis)  corresponds  with  the  temporal  artery,  and  takes  its  rise 
from  the  terminating  ramifications  of  the  latter.  It  is  imme- 
diately below  the  skin.  Its  branches  communicate  freely  with 


252  CIRCULATORY  SYSTEM. 

each  other,  and  with  the  branches  of  the  frontal  and  of  the  occi- 
pital vein:  at  the  zygoma  it  receives  the  trunk  of  the  Middle 
Temporal  Vein,  which,  collecting  the  blood  from  the  temporal 
muscle  and  other  parts  within  the  zygoma,  perforates  the  tem- 
poral fascia  to  discharge  itself  into  the  superficial  temporal  vein. 

/  The  Temporal  Vein,  (Vena  Temporalis^  which  is  formed 
by  the  junction  of  the  Middle  and  the  Superficial  Temporal, 
descends  over  the  root  of  the  zygoma,  in  company  with  the  ar- 
tery, and  penetrates,  like  the  latter,  through  the  substance  of  the 
parotid  gland.  It  is  joined,  near  the  neck  of  the  lower  jaw,  by 
the  internal  maxillary  vein.  It  is  also  joined,  in  its  descent 
through  the  parotid  gland,  by  the  anterior  auricular  veins,  by 
the  parotid  veins,  and"  by  the  transverse  facial,  all  of  which  cor- 
respond with  the  arteries  of  the  same  name.  The  temporal  vein, 
on  issuing  from  the  parotid  gland,  immediately  afterwards  be- 
comes the  External  jugular;  but,  occasionally,  it  ends  wholly  or 
in  part  in  the  internal  jugular. 

The  Internal  Maxillary  Vein  (Vena  Maxillaris  Internd]  is 
derived  from  the  terminating  ramifications  of  all  the  arteries 
into  which  the  internal  maxillary  is  divided;  it  is,  therefore, 
composed  of  the  spheno-palatine  vein,  which  brings  the  blood 
from  the  nose,  of  the  infra-orbital,  of  the  pterygoids,  inferior 
maxillary,  deep-seated  temporal,  and  so  forth,  with  the  excep- 
tion of  the  vein,  which  might  belong  to  the  middle  artery  of 
dura  mater,  but  which  does  not  exist  according  to  Portal  and  to 
Hippolytus  Cloquet.  But,  by  the  aid  of  the  spheno-palatine 
vein,  the  internal  maxillary  communicates  with  the  sinuses  in 
the  bottom  of  the  cranium,  by  branches,  called  the  Emissary 
Veins  of  Santorini,*  which  pass  through  the  foramen  ovale,  ro- 
tundum,  and  spinale.  It  also  communicates  with  the  plexus  of 
veins  on  the  side  of  the  pharynx. 

The  External  Jugular  Vein  (Vena  Jugularis  Externa)  is  the 
continuation  of  the  temporal.  It  descends  on  the  neck  almost 
vertically,  between  the  platysma  myodes  and  the  sterno-mas- 

*  Obs.  Anat.  chap.  iii.  p.  74. 


VEINS  OF  THE  HEAD  AND  NECK.  253 

loideus,in  the  direction  of  the  fibres  first,  and  crossing  those  of  the 
latter  obliquely.  Just  behind  the  clavicle,  at  the  external  mar- 
gin of  the  sterno-mastoideus,  it  opens  into  the  subclavian  vein, 
in  front  of  the  scalenus  anticus  muscle.  Sometimes,  instead  of 
one  trunk  only,  there  are  two  or  three,  which  unite  at  a  varia- 
ble distance  above  the  subclavian.  This  vein  varies  also  in  its 
size,  and  in  the  branches  from  which  it  is  made  up:  sometimes 
it  receives  the  facial  vein,  and  on  other  occasions  the  latter  runs, 
as  stated,  into  the  internal  jugular.  The  condition  and  arrange- 
ment of  the  internal  and  external  jugulars  are,  indeed,  so  incon- 
stant, in  regard  to  the  trunks  that  compose  them,  that  it  is 
scarcely  possible  to  give  more  than  a  very  general  description 
of  them  with  tolerable  accuracy. 

The  external  jugular,  in  going  down  the  neck,  anastomoses 
more  or  less  with  the  internal  jugular,  either  directly  or  by  its 
branches:  one  of  these  anastomoses  is  found  near  the  angle  of 
the  lower  jaw,  about  the  trunk  of  the  facial  vein,  and  is  so  large 
as  to  explain  the  difference  of  opinion  among  anatomists  in  re- 
gard to  the  latter's  termination.  Sometimes  the  occipital  vein, 
or  a  large  trunk  from  it,  joins  the  external  jugular.  At  the 
lower  part  of  the  neck,  the  external  jugular  is  augmented  by 
the  superficial  cervical  veins.  Some  of  these  come  from  the 
lower  part  of  the  neck,  near  the  shoulder,  and  join  the  jugular 
just  above  the  clavicle;  others  are  placed  on  the  lower  front 
part  of  the  neck,  above  the  sternum,  and  there  form  with  each 
other  a  remarkable  and  an  irregular  plexus,  consisting  in  nu- 
merous meshes.  It  frequently  happens  that  the  external  jugu- 
lars of  the  two  sides,  just  before  they  terminate,  anastomose 
with  each  other  by  a  large  horizontal  trunk,  which  runs  just 
above  the  end  of  the  sternum,  in  front  of  the  sterno-mastoid, 
sterno-hyoid,  and  the  thyroid  muscles:  this  trunk,  on  other  oc- 
casions, goes  more  deeply,  and  behind  these  muscles,  from  one 
subclavian  vein  to  another,  or  to  a  jugular;  its  mode  of  attach- 
ment is,  indeed,  much  varied:  when  it  exists,  however,  it  fre- 
quently receives  several  of  the  superficial  veins  of  the  neck,  and 
the  inferior  thyroidal. 

The  Internal  Jugular  Vein  (Vena  Jugularis  Inferno)  extends 
from  the  basis  of  the  cranium  to  the  internal  margin  of  the  first 
VOL.  II.— 33 


254  CIRCULATORY  SYSTEM. 

rib,  at'the  insertion  of  the  scalenus  anticus  muscle.  The  lateral 
sinuses  of  the  dura  mater,  receiving  ultimately  all  the  blood  of 
the  brain,  of  the  eye,  and  a  portion  of  that  of  the  nose,  convey 
it  from  the  cranium  through  the  posterior  foramina  lacera, 
where  they  are  joined  to  the  upper  end  of  the  internal  jugular 
veins,  the  lining  membrane  of  each  sinus  being  continuous  with 
that  of  its  respective  veins.  Each  vein  is  somewhat  enlarged 
at  its  commencement,  which  is  therefore  called  its  Gulf  or  Sinus; 
the  right  vein  is  frequently  larger  than  the  left.  ,  The  internal 
jugular  then  descends  in  front  of  the  transverse  processes  of  the 
vertebrae  of  J-he  neck,  on  the  outer  side  of  the  internal  end  of 
the  primitive  cais^tid  artery,  and  of  the  pneumogastric  nerve. 
It  is  concealed  above  by  the  styloid  process  of  the  temporal 
bone,  and  the  muscles  belonging  to  it;  it  is  crossed,  half  way 
down  the  neck,  by  the  omo-hyoideus  muscle;  and,  in  the  great- 
er part  of  its  course,  is  beneath,  and  nearly  parallel  with  the 
anterior  edge  of  the  sterno-mastoideus.  Having  got  behind  the 
sternal  end  of  the  clavicle,  it  is  joined  at  the  internal  edge  of 
the  scalenus  anticus  by  the  subclavian  vein,  and  the  union  of 
the  two  forms  the  vena  innominata. 

The  internal  jugular  receives  frequently  a  large  anastomotic 
branch,  just  alluded  to,  from  the  external  jugular,  at  the  under 
margin  of  the  parotid  gland,  between  the  digastric  muscle  and 
the  lower  jaw,  and  it  is  in  this  vicinage  that  it  is  generally  re- 
enforced  by  the  Occipital;  the  Lingual;  the  Facial;  the  Pha- 
ryngeal;  and  the  Superior  Thyroidal  Veins,  that  have  been 
described. 

The  Vena  Innominata,  or  Brachio  Cephalic  Vein,  is  the  trunk 
formed  on  either  side  by  the  junction  of  the  subclavian  with  the 
internal  jugular.  On  the  right  side  it  looks  like  the  continua- 
tion of  the  internal  jugular,  and  descends  in  contact  with  the 
right  pleura,  behind  the  right  side  of  the  sternum,  for  the  dis- 
tance of  an  inch  or  thereabouts.  On  the  left  side  it  crosses  be- 
hind the  superior  end  of  the  sternum,  descending  obliquely  in 
this  course,  from  left  to  right,  until  it  joins  the  trunk  on  the 
right  side.  It  lies  in  front  of  the  great  vessels  proceeding  from 
the  arch  of  the  aorta;  and  is  much  longer  than  the  trunk  of  the 
other  side. 


VEINS  OP  THE  HEAD  AND  NECK.  255 

The  Vena  Cava  Superior,  or  Descendens,  arise  from  the 
junction  of  the  two  venae  innominate.  It  begins  between  the 
cartilage  of  the  first  rib  on  the  right  side,  and  the  arch  of  the 
aorta,  and  descends  to  the  superior  posterior  part  of  the  right 
auricle,  into  which  it  empties  itself.  Its  course  is  not  entirely 
vertical,  but  inclining  somewhat  to  the  left  side  and  forward. 
It  is  about  three  inches  long.  The  superior  third  of  it  is  free, 
and  is  in  contact  on  the  right  with  the  pleura,  and  on  the  left 
with  the  arteria  innominata;  the  remaining  portion  of  it  is  in- 
vested by  the  pericardium,  and  has  the  aorta  on  its  left  anterior 
face.* 

ksr" 

The  following  venous  trunks  discharge  into  the  venae  inno- 
minatie,  or  into  the  descending  cava.  The  Inferior  Thyroidal; 
the  Vertebral;  the  Superior  Intercostal;  the  Internal  Mammary; 
the  Vena  Azygos,  and  some  others  of  smaller  size. 

1.  The  Inferior  Thyroid  Vein  (Vena  Thyroidea  Inferior) 
arises  from  the  inferior  part  of  the  thyroid  gland,  by  many 
small  roots,  which  anastomose  with  those  of  the  opposite  side. 
It  descends  in  front  of  the  trachea,  involved  in  the  loose  cellu- 
lar and  fatty  matter  lying  upon  it,  and  empties  itself  into  the 
left  brachio-cephalic  vein. 

There  is  occasionally  another  thyroid  vein,  called  the  mid- 
dle, which  discharges  itself  into  the  lower  part  of  the  internal 
jugular. 

2.  The  Vertebral  Vein  ( Vena  Vert ebr alls]  is  placed  in  the 
same  canal  with  the  vertebral  artery.     At  its  upper  extremity 
it  anastomoses  with  the  occipital  sinus,  by  a  branch  lodged  in 
the  posterior  condyloid  foramen.,     In  its  descent  of  the  canal  of 
the  transverse  processes,  it  communicates  at  each  intervertebral 
foramen  with  the  vertebral  sinuses,  and  also  receives  a  branch 
from  the  muscles  of  the  neck.     It  issues  at  the  sixth  transverse 
process,  and  going  on  the  right  side  behind  the  subclavian  ar- 
tery, but  on  the  left,  in  front  of  it,  it  is,  finally,  emptied  into  the 
commencement  of  the  vena  innominata. 

*  In  some  very  rare  -cases  there  have  been  two  descending  venae  cavse,  one 
for  the  right  side  and  the  other  for  the  left.  J.  F.  Meckel. 


256  CIRCULATORY  SYSTEM. 

3.  The  Superior  Intercostal  Vein  ( Vena  Inter  cost  alis  Supe- 
rior} is  on  the  right  side  an  inconsiderable  trunk,  sometimes 
deficient,  which  commences  by  branches  belonging  to  the  two 
first  intercostal  spaces,  and  empties  into  the  vena  innominata 
just  below  the  vertebral.     On  the  left  side  it  is  much  larger, 
and  arises  from  the  six  or  eight  superior  intercostal  spaces.     It 
lies  on  the  left  side  of  the  bodies  of  the  upper  dorsal  vertebrae, 
and  at  each  intercostal  space,  as  it  ascends,  receives  its  contri- 
bution of  an  intercostal  vein,  corresponding  with  the  intercostal 
artery;  it  also  receives  branches  from  the  oesophagus,  and  about 
the  third  dorsal  vertebra  the  left  bronchial  vein  is  discharged 
into  it.     Issuing  from  the  thorax  above,  it  discharges  into  the 
left  vena  innominata  near  its  commencement. 

4.  The  Internal  Mammary  Vein  ( Vena  Mammaria  Interna) 
arises  from  the  terminating  branches  of  the  internal  mammary 
artery,  and  in  its  .situation  and  course  corresponds  with  the  lat- 
ter.    It  is  re-enforced  by  small  branches  from  the  diaphragm, 
the  pericardium,  and  the  thymus  gland.     Each  internal  mam- 
mary vein  discharges  itself  on  its  respective  side  into  the  vena 
innominata  near  the  superior  intercostal. 

5.  The  Vena  Azygos  is  placed  in  the  posterior  mediastinum, 
on  the  right  anterior  margin  of  the  Dorsal  Vertebrae,  and  dis- 
charges itself  in  making  an  arch  forwards  over  the  root  of  the 
right  lung,  into  the  descending  cava,  just  above  the  introduction 
of  the  latter  into  the  pericardium.     Its  orifice  there  is  supplied 
with  a  membranous  duplicature  or  valve,  which  prevents  the 
blood  once  discharged  from  the  re-entering  it.     The  valve  is 
sometimes  double,  and  also  somewhat  removed  from  the  orifice. 
It  was  the  observation  of  these  valves,  first  of  all,  which  called 
the  attention  of  Sylvius  and  of  Charles  Etienne  to  their  existence 
in  other  veins. 

This  vein  begins  in  the  abdomen,  either  by  an  anastomosis 
with  the  ascending  cava,  or  with  the  upper  lumbar  vein;  it 
then  ascends  into  the  thorax  through  the  aortic  orifice  of  the 
diaphragm,  and  continuing  to  mount  upwards  beneath  the  pleura, 
it  lies  on  the  right  side  of  the  thoracic  duct,  and  crosses  in  front 
of  the  intercostal  arteries  of  the  right  side.  In  this  course,  it 


VEINS  OF  THE  HEAD  AND  NECK.  257 

receives  from  the  ten  inferior  intercostal  spaces  of  the  right  side, 
their  respective  intercostal  veins  corresponding  in  their  origin 
and  course  with  the  intercostal  arteries.  About  the  sixth  ver- 
tebra of  the  back,  it  receives  a  trunk  ( Vena  Hemiazygos]  which 
is  formed  from  the  four  or  six  lower  intercostal  veins  of  the  left 
side,  and  commences  in  the  abdomen,  also,  by  anastomosis  with 
the  left  emulgent  vein  or  the  left  superior  lumbar,  and  which 
gets  into  the  thorax  either  through  the  aortic  orifice  of  the  dia- 
phragm, or  through  a  special  opening  to  the  left  of  it.  The 
vena  azygos  also  receives  some  small  ramifications  from  the 
oesophagus,  and  near  the  fourth  dorsal  vertebra,  the  right  bron- 
chial vein  is  discharged  into  it.  Other  small  ramifications  join 
it  from  the  parietes  of  the  descending  cava  of  the  aorta,  and  of 
the  right  pulmonary  artery.  Branches  also  proceed  to  it,  or  to 
the  intercostal  veins,  from  the  interior  of  the  vertebral  canal  at 
each  intervertebral  foramen. 

This  vein  is  commonly  spoken  of  by  anatomists,  as  forming 
a  great  anastomosis  between  the  ascending  and  the  descending 
cava.  The  tendency  to  establish  this  anastomosis  is  strikingly 
confirmed  by  a  preparation  made  by  myself,  when  I  was  a  stu- 
in  this  institution,  in  1813,  and  now  in  the  Anatomical  Cabinet, 
where  the  ascending  cava,  instead  of  emptying,  as  usual,  into 
the  lower  part  of  the  right  auricle,  ascended  on  the  right  side 
of  the  dorsal  vertebrae,  and  supplanting  in  situation  and  office 
the  vena  azygos,  discharged  itself  into  the  descending  cava,  in 
a  manner  corresponding  with  the  vena  azygos,  by  making  a 
curvature  forwards  over  the  root  of  the  right  lung. 

The  Sinuses  of  the  Vertebral  Column*  (Sinus  Columnae 
Vertebralis)  are  situated  in  the  vertebral  cavity,  on  the  pos- 
terior face  of  the  bodies  of  the  vertebras,  and  in  front  of  the 
dura  matter  of  the  spinal  marrow.  They  are  two  long  veins, 
one  at  each  margin  of  the  posterior  vertebral  ligament,  and  ex- 
tend from  the  foramen  magnum  occipitis  to  the  inferior  end  of 
the  sacrum.  They  are  maintained  in  their  places  by  a  loose 
cellular  tissue  between  the  bones  and  the  dura  mater,  and,  there- 
fore, unlike  the  sinuses  of  the  brain,  are  entirely  independent 
of  the  dura  mater. 

*  G.  Breschet,  Essai  sur  les  Veines  du  rachis.     Paris,  1819. 


258  CIRCULATORY  SYSTEM. 

These  sinuses  are  small  where  they  begin  in  the  sacrum,  and 
are  there  merely  two  cylindrical  veins  surrounded  by  the  loose 
cellular  matter,  and  which  have  an  anastomosis  between  them. 
In  ascending  the  spine  they  enlarge,  but  not  continually,  as 
they  are  somewhat  smaller  in  the  cervical  than  in  the  dorsal 
vertebrae.  On  the  body  of  each  vertebra  they  are  rather  larger 
than  on  the  intervertebral  substance:  this  givres  them  a  knotted 
appearance,  which  is  especially  distinct  in  the  loins. 

At  the  middle  of  each  vertebra  they  are  joined  to  one  an- 
other by  transverse  branches,  which  pass  beneath  the  posterior 
vertebral  ligament,  and  receive  the  veins  belonging  to  the  can- 
cellous  structure  of  the  bone.  Externally,  they  communicate 
with  thfc  vertebral  veins  in  the  transverse  processes  of  the  neck, 
with  the  intercostal,  and  with  the  lumbar  veins,  as  an  opening 
occurs  between  the  adjacent  vertebrae.  They  also  receive  many 
delicate  veins  from  the  dura  mater  of  the  spine.  These  two 
trunks  terminate  at  their  upper  end  by  an  anastomosis,  through 
the  anterior  condyloid  foramen,  with  the  internal  jugular:  they 
also  terminate  by  anastomosis  with  the  anterior  occipitaUsinus 
and  with  the  vertebral  veins. 

From  the  arrangement  of  these  sinuses,  it  appears  that  each 
bone  of  the  spine  has  its  own  venous  system  or  circle;  which 
also  is  the  case  in  regard  to  the  corresponding  section  of  me- 
dulla spinalis  in  early  life,  when  it  occupies  the  whole  length 
of  the  spine.  Each  of  these  circles,  by  the  freedom  of  their 
anastomoses,  therefore,  forms  a  link  in  a  long  chain  of  venous 
circles  belonging  to  the  structure  of  the  spine. 


SECT.   II. OP  THE  VEINS  OP  THE  TIPPER  EXTREMITIES. 

The  veins  of  the  upper  extremities  are  superficial  and  deep- 
seated,  and  arise  from  the  distribution  of  the  axillary  artery. 

The  Deep-seated  Veins  are  found  in  company  with  each  ar- 
terial ramification,  there  being  two  veins  to  one  artery  gene- 
rally. We  thus  have  them  observing  the  course  of  the  arteries 
of  the  hand,  of  the  fore  arm,  of  the  arm,  and  of  the  shoulder. 
At  the  bend  of  the  arm,  the  two  radial  and  the  two  ulnar  veins 


VEINS  OF  THE  UPPER  EXTREMITIES.  259 

coalesce  into  the  two  brachial  veins,  which  attend  the  brachial 
artery,  one  on  each  of  its  sides,  and  at  intervals  thrbw  anasto- 
motic  branches  across  it.  Sometimes,  but  one  of  these  trunks 
exists,  with  the  exception  of  the  lower  part  of  the  arm,  where 
there  are  most  commonly  two.  The  trunk  (or  trunks,  as  the 
case  may  be,)  is  joined  by  the  basilic  vein,  at  a  point  varying 
from  the  middle  of  the  arm  to  the  axilla.  These  venae  comites, 
or  satellites,  are  invariably  called  after  the  arteries  which  they 
attend,  and  having  no  difference  from  the  latter  in  relative  si- 
tuation, a  farther  description  of  them  may  be  dispensed  with. 

The  Superficial  Veins  lie  between  the  skin  and  the  brachial 
aponeurosis,  and  are  considerably  larger  than  the  preceding. 
Their  earliest  roots  are  seen  on  the  back  of  the  fingers;  they 
then  appear  on  the  back  of  the  hand,  on  the  posterior  face  of 
the  lower  end  of  each  interosseous  space.  There  are  commonly 
six  trunks  in  all:  the  one  on  the  ulnar  side  of  the  hand,  and 
the  three  next  to  it,  converge  towards  the  middle  of  the  back 
of  the  carpus  into  a  single  trunk;  the  two  others,  one  of  which 
comes  from  the  thumb  and  the  other  from  the  back  of  the  fore- 
finger, converge  to  the  outer  end  of  the  carpus,  and  there  form 
a  single  trunk  also.  Between  these  several  trunks,  there  are 
frequent  anastomoses,  and  they,  finally,  assemble  into  two  prin- 
cipal branches  called  the  Cephalic  and  the  Basilic  Vein. 

The  Cephalic  Vein  (Vena  Cephalica,  Radialis  Cutanea]  is 
the  trunk  which  comes  from  the  thumb  and  from  the  fore  fin- 
ger, and  has  at  first  the  name  of  Cephalica  Pollicis.  It  ranges 
along  the  anterior  and  radial  margin  of  the  fore  arm,  and  re- 
ceives, continually,  an  augmentation  from  small  collateral 
branches  on  the  back  of  the  fore  arm.  Having 'reached  the 
bend  of  the  arm,  it  then*  ascends  along  the  external  margin  of 
the  biceps  flexor  cubiti  till  it  reaches  the  lower  margin  of  the 
pectoralis  major  muscle;  it  then  rises  superficially  along  the  in- 
terstice between  this  muscle  and  the  deltoid,  to  within  eight  or 
ten  lines  of  the  clavicle,  where  it  dips  down  to  join  the  axillary 
vein.  Along  the  arm,  it  receives  some  small  secondary  cuta- 
neous branches. 


260  CIRCULATORY  SYSTEM. 

The  Basilic  Vein  (Vena  Basilica,  Cubitalis  Cutanea]  is 
larger  than  the  cephalic,  and  begins  by  the  trunk  which  comes 
from  the  ulnar  side  of  the  back  of  the  hand,  and  is  first  called 
the  Vena  Salvatella.  On  the  fore  arm,  the  basilic  frequently 
consists  in  two  long  trunks,  the  anterior  and  the  posterior:  in 
this  case,  the  posterior  is  the  principal  one,  and  runs  along  the 
internal  posterior  edge  of  the  ulna  until  it  comes  to  the  bend  of 
the  arm;  it  then  mounts  over  the  latter,  rising  obliquely  in  front 
of  the  internal  condyle.  The  anterior  branch  begins  near  the 
palm  of  the  hand,  runs  up  in  front  of  the  ulnar  side  of  the  fore 
arm,  and  discharges  itself  into  the  median  basilic  vein  over  the 
brachial  artery  in  front  of  the  bend  of  the  arm.  These  two 
trunks,  or  one  as  the  case  may  be,  receive  the  cutaneous  veins 
belonging  to  the  ulnar  side  of  the  fore  arm. 

Above  the  elbow  joint,  the  basilic  gets  below  the  fascia  of 
the  arm  at  the  inner  edge  of  the  biceps,  and  about  the  middle 
of  the  arm  becomes,  by  its  junction  with  the  venae  satellites, 
the  Brachial  Vein;  but  sometimes,  as  mentioned,  this  junction 
occurs  much  higher  up. 

s'  The  Median  Vein  ( Vena  Mediana]  arises,  by  branches,  from 
the  wrist,  from  the  palm  of  the  hand,  and  from  the  middle  of 
the  front  of  the  fore  arm.  It  forms  a  trunk  which  ascends  in 
front  of  the  fore  arm,  and  which,  a  few  inches  below  the  bend 
of  the  arm,  divides  into  two.  One  branch  runs  outwardly,  in 
ascending  for  an  inch  or  two,  and  joins,  at  the  outer  side  of  the 
bend  of  the  arm,  the  cephalic  vein;  it  is  called,  therefore,  the 
Median  Cephalic.  The  other  branch  continues  to  ascend,  and, 
crossing  obliquely  the  direction  of  the  brachial  artery,  it  re- 
ceives, near  the  latter,  the  anterior  trunk  of  the  basilic  vein, 
and  somewhat  above  the  bend  of  the  arm,  runs  into  the  proper 
basilic  vein:  it  is  called  the  Median  Basilic. 

There  is  frequently  a  departure ^rom  the  preceding  arrange- 
ment of  the  median  vein;  the  most  common  is  where  a  trunk 
begins  from  the  cephalic,  below  the  bend  of  the  arm,  and  runs 
obliquely  in  front  of  the  latter  to  join  the  main  trunk  of  the 
basilic  above  the  elbow  joint.  This  oblique  trunk  stands  in  the 
place  of  median  cephalic  and  median  basilic,  and  receives  sue- 


VEINS  OP  THE  UPPER  EXTREMITIES.  261 

cessively  the  median,  the  anterior,  and  the  posterior  basilic.  It 
is  frequently  the  median  itself,  and  has  a  short  anastomosis,  in 
such  case,  with  the  cephalic  vein. 

The  Superficial  Veins  anastomose  frequently  with  each  other, 
so  that,  when  they  are  all  fully  injected,  a  plexus  of  veins  is 
found  immediately  beneath  the  skin  of  the  upper  extremity 
from  one  end  to  the  other.  The  Venae  Satellites  also  anasto- 
mose frequently  by  branches  which  cross  the  artery  to  which 
they  belong.  At  the  bend  of  the  arm,  at  the  wrist,  and  in  dif- 
ferent places,  there  are  also  anastomoses  between  the  deep-seat* 
ed  and  the  superficial  veins. 
• 

The  Axillary  Vein  ( Vena  Axillaris)  results  from  the  union 
of  the  basilic  with  the  brachial  vein.  It  is  below  and  in  front 
of  the  axillary  artery,  being  included  in  the  same  sheath  with 
it,  and  also  involved  with  the  axillary  plexus  of  nerves.  It  re- 
tains its  name  from  the  lower  margin  of  the  arm  pit  to  the  un- 
der surface  of  the  clavicle,  where,  like  the  artery,  it  is  then 
called  subclavian.  In  this  course  it  is  joined  near  the  points 
where  the  corresponding  arteries  are  given  off,  by  the  Anterior 
and  the  Posterior  Circumflex  Veins;  by  the  Scapular;  and  by 
the  External  Thoracic. 

'  The  Subclavian  Vein  (Vena  Subclavia)  extends  from  the 
termination  of  the  axillary  to  the  vena  innominata,  where  the 
latter  is  constituted  by  the  junction  of  the  internal  jugular  with 
the  subclavian.  In  its  course  it  goes  under  the  subclavian  mus- 
cle, and  is  in  front  of  the  subclavian  artery  from  the  beginning, 
but  near  it:  afterwards  it  is  separated  from  the  artery  by  the 
latter  going  between  the  anterior  and  the  middle  scalenus  mus- 
cle; whereas  the  vein  runs  over  the  anterior  end  of  the  first 
rib,  in  front  of  the  insertion  of  the  scalenus  anticus. 

The  Subclavian  Vein  is  joined  by  some  branches  coming 
from  the  shoulder  and  from  the  lower  part  of  the  neck,  and,  at 
the  outer  margin  of  the  origin  of  the  sterno-mastoid  muscle:  it 
is  augmented  by  the  addition  to  it  of  the  external  jugular.  It 
terminates  at  the  internal  margin  of  the  scalenus  anticus,  as 
mentioned  in  the  vena  innominata. 
VOL.  II.— 34 


262  CIRCULATORY  SYSTEM. 


"SECT.  III. VEINS  OF  THE  LOWER  EXTREMITIES. 

The  veins  of  the  lower  extremities,  like  those  of  the  upper,  are 
deep-seated  and  superficial.  The  former  follow  the  course  of 
the  arteries,  and  are  the  venae  satellites;  there  being,  for  the 
most  part,  two  veins  for  every  artery  as  far  up  as  the  ham,  and 
also  as  regards  the  muscular  branches  of  the  thigh.  These  venae 
satellites  adhere  closely  to  the  artery,  and  are  separated  from 
each  other  by  the  latter.  They  also  have  frequent  anastomoses 
with  each  other  across  the  artery. 

The  Popliteal  Vein  ( Vena  Poplitea)  is  a  single  trunk  formed 
fey  the  union  of  the  anterior  tibial,  the  posterior  tibial,  and  the 
peroneal  veins.  It  begins  on  the  posterior  part  of  the  head  of 
the  tibia,  and  extends  upwards  through  the  ham  to  the  perfora- 
tion in  the  adductor  magnus  muscle,  which  transmits  the  femo- 
ral artery.  It  is  situated  on  the  posterior  face  of  the  popliteal 
artery,  to  which  it  closely  adheres;  and  behind  it  is  the  popliteal 
nerve,  the  continuation  of  the  great  sciatic. 

The  Femoral  Vein  (Vena  Femoralis)  is  the  continuation 
upwards  of  the  popliteal:  it  at  first  is  placed  behind  the  artery, 
but  in  a  short  space  it  gets  to  its  interior  face,  and  continues  to 
adhere  to  it,  in  that  situation,  up  to  Poupart's  ligament,  where 
it  becomes  the  external  iliac  vein.  At  the  usual  distance  below 
the  groin,  where  the  arteria  profunda  is  given  off,  the  femoral 
vein  receives  the  vena  cruralis  profunda,  which  is  derived  from 
the  branches  of  this  artery,  and  is  rather  more  superficial  than 
•it;  the  two,  however,  adhere  closely  together.  Just  below 
Poupart's  ligament  the  femoral  vein  receives  several  small 
branches  of  vein-s  corresponding  with  the  external  pudic  arte- 
ries. 

j 

The  Small  Saphena  ( Vena  Saphena  Minor  Externa)  com- 
mences by  several  small  branches  near  the  external  side  of  the 
•top  of  the  foot,  and  the  external  ankle;  a  trunk  is  formed  by 
behind  cthe  latter,  which  ascends  along  the  tendo-achillis 
the  posterior  face  of  the  gastrocnemius  muscle,  collecting 


VEINS  OF  THE  LOWER  EXTREMITIES.  263 

several  small  veins  from  the  back  of  the  leg  in  its  course.  This 
vein  is  superficial  in  its  whole  course,  being  placed  immediate- 
ly beneath  the  skin.  In  the  ham,  it  goes  fora  short  distance 
along  the  internal  face  of  the  popliteal  nerve,  and  then  makes  a 
dip  through  the  adipose  matter  there  to  empty  into  the  popli- 
teal vein. 

It  is  said,  by  Portal,  that  the  branches  of  this  vein  become 
very  apparent  in  persons  who  suffer  from  podagra,  and  from  en- 
largements of  the  lymphatic  glands  in  the  ham.  In  such  case 
their  distention  has  been  relieved  by  the  application  of  leeches 
along  them. 

/  The  Great  Saphena  ( Vena  Saphena  Magna  Internet)  is  also- 
superficial,  has  its  primitive  roots  coming  from  the  internal  up- 
per part  of  the  foot,  and  from  the  sole  of  the  latter.  These 
branches  are  assembled  into  a  trunk  which  passes  upwards  in 
front  of  the  internal  ankle,  then  ascends  along  the  internal  face 
of  the  leg,  in  a  line  corresponding  with  the  posterior  margin  of 
the  tibia.  The  great  saphena  continues  its  ascent  over  the  in- 
ternal condyle  near  its  posterior  part,  and  then  mounts  up  the 
internal  face  of  the  thigh,  in  a  line  corresponding  nearly  with 
the  internal  margin  of  the  sartorius  muscle.  It  finally  termi- 
nates in  the  femoral  vein  about  twelve  or  eighteen  lines  below 
Poupart's  ligament,  an  opening  being  left  in  the  fascia  femoris 
for  this  purpose. 

In  the  whole  of  this  course  the  great  saphena  is  situated  be- 
tween the  skin  and  the  fascia  of  the  lower  extremity ;  it  is,  con- 
sequently, so  superficial,  that  in  persons  of  moderate  corpulency 
it  is  very  visible,  and  by  slight  pressure  above,  along  with  the 
erect  position,  it  becomes  so  much  swollen,  that  it  is  easily 
opened  with  the  lancet  where  it  passes  over  the  internal  ankle. 
It  receives,  in  its  ascent,  small  branches  from  the  anterior  and 
posterior  part  of  the  leg,  from  the  corresponding  surfaces  of  the 
thigh,  and  near  its  termination  it  gets  a  few  of  the  external  pu- 
dendal  veins. 

When  the  great  and  the  small  saphena  veins  are  successfully 
injected,  their  branches  are  seen  to  form  a  considerable  num- 
ber of  anastomoses,  which  thereby  produce  a  remarkable  venous 


264  CIRCULATORY  SYSTEM. 

net-work,  just  beneath  the  skin  of  the  whole  inferior  extre- 
mity. 


SECT.  IV. VEINS  OP  THE  ABDOMEN. 

The  External  Iliac  Vein,  (Vena  Iliaca  Externa,}  being  the 
continuation  of  the  femoral  vein,  passes  into  the  abdomen,  un- 
der Poupart's  ligament,  and  in  contact  with  the  internal  margin 
of  the  external  iliac  artery.  It  there  receives  the  epigastric, 
and  the  circumflex  iliac  veins,  corresponding  with  the  arteries 
of  the  same  name;  it  also  receives  a  vein  of  some  size,  which 
enters  by  the  abdominal  canal  in  adhering  to  the  spermatic 
chord,  and  which  comes  from  the  coats  of  the  testicle.*  It 
keeps  then  along  the  internal  side  of  the  artery,  somewhat  be- 
hind it,  at  the  superior  margin  of  the-  pelvis,  and  joins  the  hy- 
pogastric  vein  opposite  to  the  sacro-iliac  junction,  and  thereby 
forms  the  common  iliac  vein. 

The Hypogastric  Vein  (Vena  Hypogastrica,  Iliaca  Interna) 
comes  from  the  inferior  part  of  the  pelvis  in  front  of  the  sacro- 
iliac  junction,  and  in  company  with  the  hypogastric  artery.  It 
arises  by  branches  corresponding  with  the  distribution  of  the 
latter  to  the  viscera  of  the  pelvis,  and  to  its  external  parts;  these 
branches  are  so  numerous  at  particular  points,  and  'have  such 
frequent  anastomoses,  that  they  are  often  named  Plexus.  Thus, 
there  is  a  hemorrhoidal  plexus  for  the  lower  part  of  the  rectum, 
a  vesicle  for  the  bladder,  a  sacral  for  the  sacrum,  a  pudendal  for 
the  parts  of  generation  in  the  male,  a  vaginal  for  the  vagina, 
and  a  uterine  for  the  uterus  of  the  female. 

The  Plexus  Hemorrhoidalis,  besides  being  connected  with 
the  hypogastric,  also  anastomoses  with  the  branches  of  the  vena 
portarum. 

The  Plexus  Vesicalis  is  different  in  the  two  sexes.  In  man 
it  commences  at  the  extremity  of  the  penis  by  several  branches, 
which  unite  into  two  trunks  of  considerable  size,  the  Venae 
Dorsales  Penis.  The  latter  go  along  the  upper  face  of  the  pe- 
nis, near  or  at  its  middle,  to  the  symphysis  of  the  pubes,  con- 

•  II.  Cloquet,  Traite  D'Anat. 


VEINS  OP  THE  ABDOMEN.  265 

tinually  receiving  in  this  course  small  trunks  from  the  integu- 
ments of  the  penis  and  from  the  scrotum.  They  then  get  into 
the  pelvis,  between  the  root  of  the  penis  and  the  symphysis  pu- 
bis,  and  continue  horizontally  backwards  on  the  side  of  the  pro- 
state gland,  of  the  vesiculae  seminales,  and  of  the  lower  fundus 
of  the  bladder.  They  receive  many  branches  from  these  parts, 
which,  with  the  frequency  of  the  anastomoses  about  here,  con- 
stitute the  vesical  plexus.  The  latter,  finally,  discharges  into 
the  lower  part  of  the  hypogastric  vein  by  two  or  more  branches. 
In  the  female  the  vesical  plexus  begins  on  the"dorsum  of  the 
clitoris,  by  several  branches  coming  from  it  and  from  the  vul- 
va; they  get  into  the  pelvis  under  the  symphysis  pubis,  and  on 
the  sides  of  the  urethra  and  of  the  vagina,  forming  upon  the 
lower  part  of  the  bladder,  and  on  the  side  of  the  vagina,  with 
the  assistance  of  branches  from  these  viscera,  a  remarkable 
plexus,  which  also  empties  into  the  internal  iliac  vein. 

The  Plexus  Sacralis  consists  in  an  order  of  veins,  anastomosing 
freely  with  each  other,  and  corresponding  with  the  middle  and 
the  lateral  sacral  veins.  They  communicate  with  the  inferior 
end  of  the  vertebral  sinuses  through  the  anterior  sacral  forami- 
na; they  also  communicate  with  the  hemorrhoidal  and  with  the 
vesical  veins.  They  terminate  in  the  venous  trunks,  nearest 
the  origin  of  the  arteries  from  which  they  are  derived. 

The  Plexus  Pudendalis  is  derived  from  the  branches  of  the 
internal  pudic  vein  which  go  to  the  perineum,  to  the  posterior 
part  of  the  scrotum,  and  to  the  integuments  of  the  under  part 
of  the  penis.  The  trunk  formed  by  the  assembling  of  these 
several  ramifications,  follows  the  course  of  the  artery  to  which 
it  belongs,  and  gets  into  the  pelvis  at  the  lower  part  of  the 
sciatic  foramen,  where  it  contributes  to  the  formation  of  the  hy- 
pogastric vein.  • 

The  Plexus  Uterinus  consists  in  a  considerable  number  of 
veins,  which  are  distributed  upon  the  surface,  and  in  the  texture 
of  the  uterus;  they  are  also  found  in  abundance  in  the  broad  li- 
gaments, where  they  anastomose  with  the  ovarian  veins. 

The  Plexus  Vaginalis  comes  from  the  anterior  parts  of  the 
organs  of  generation  constituting  the  vulva,  as  the  labia  majora, 
minora,  and  so  on.  It  also  arises  from  the  whole  surface  of  the 


266  CIRCULATORY  SYSTEM. 

vagina,  surrounds  it  completely,  and  anastomoses  with  the  ute- 
rine veins. 

The  Gluteal,  the  Obturator,  and  the  Ilio-Lumbar  Veins,  also 
contribute  to  the  Hypogastric;  their  description  conforms  so 
nearly  to  that  of  the  corresponding  arteries,  that  it  is  unneces- 
sary to  detail  it. 

The  Primitive  Iliac  Vein,  ( Vena  Iliaca  Primitiva,  Commu- 
ntSy)  formed  by  the  junction  of  the  External  and  of  the  Internal 
Iliacs,  extends  from  the  sacro-iliac  symphysis  to  the  lower  mar- 
gin of  the  fourth  lumbar  vertebra  on  its  right  side,  where  it  joins 
the  corresponding  trunk  of  the  opposite  side  of  the  body,  to 
form  the  commencement  of  the  ascending  vena  cava.  In  this 
course  the  left  one  passes  obliquely  across  the  body  of  the  fifth 
lumbar  vertebra,  and  beneath  the  right  primitive  iliac  artery. 

The  Vena  Cava  Inferior  is  situated  on  the  front  of  the  spinal 
column,  to  its  right  side,  and  extends  from  the  lower  part  of 
the  fourth  lumbar  vertebra;  or,  in  other  words,  from  the  junc- 
tion of  the  primitive  iliac  veins  to  the  under  end  of  the  right 
auricle  of  the  heart,  into  which  it  empties.  It  is  larger  than 
the  Descending  Cava. 

In  its  ascent  it  inclines  very  gradually  to  the  right  side  of  the 
spine,  so  as  to  reach  the  opening  in  the  tendinous  centre  of  the 
diaphragm,  through  which  it  passes  just  before  it  terminates  in 
the  auricle.  It  is  bounded  on  the  left  side  by  the  aortaf  and 
above  the  latter  it  is  in  front  of  the  left  pillar  of  the  diaphragm. 
Its  lower  extremity  is  crossed  in  front  by  the  root  of  the  pri- 
mitive iliac  artery;  it  is  also  crossed  in  its  ascent  by  the  duode- 
num and  the  pancreas.  Its  upper  extremity  is  behind  the  liver, 
and  frequently  passes  through  the  substance  of  this  viscus. 

It  receives  the  middle  sacral,  the  lumbar,  the  spermatic,  the 
.emulgent,  the  capsular,  the  hepatic,  and  the  phrenic  veins. 

The  Middle  Sacral  Vein  ( Vena  Sacra  Media)  forms,  as  has 
been  just  mentioned  in  the  account  of  the  branches  of  the  hy- 
pogastric  vein,  a  part  of  the  sacral  plexus.  Its  trunk  follows 


VEINS  OF  THE  ABDOMEN.  267 

4he  course  of  the  middle  sacral  artery  on  the  front  of  the  sacrum, 
and  discharges  into  the  commencement  of  the  vena  cava,  in  the 
fork  formed  by  the  origin  of  the  primitive  iliacs. 

The  Lumbar  Veins  ( Vense,  Lumbales)  correspond  with  the 
lumbar  arteries,  and  are  commonly  four  or  five  in  number  on 
each  side.  Their  primitive  roots  anastomose  with  the  epigas- 
tric, the  last  intercostal,  and  the  circumflex  iliac  veins;  the 
dorsal  branches  of  them  also  anastomose  with  the  vertebral 
sinuses,  through  the  intervertebral  foramina.  Their  trunks 
pass  along  with  the  arteries,  between  the  bodies  of  the  vertebra 
and  the  psoas  magnus  muscle,  or  through  the  fasciculi  of  the 
latter:  those  on  the  left  side  pass  behind  the  aorta,  in  order  to 
reach  the  vena  cava,  and  are,  consequently,  longer  than  such  as 
-are  on  the  right. 

*  The  Spermatic  Veins  ( Vense  Spermaticse.}  The  right  one 
extends  from  the  testicle  to  the  ascending  cava,  just  below  the 
emulgent  veins;  while  the  one  on  the  left  empties  into  the  left 
emulgent  vein.  They  are  larger  than  the  corresponding  arte- 
ries, and  present  some  peculiarities  in  the  two  sexes. 

In  the  male,  the  extremities  of  these  veins  begin  in  the  testi- 
cle, and  issue  from  it  through  the  tunica  albuginea;  some  of  them 
also  arise  from  the  epididymis.  They  anastomose  with  the  su- 
perficial veins  of  the  penis  and  of  the  scrotum,  and  disengaging 
themselves  from  the  tunica  vaginalis,  at  its  back  part,  are  assem- 
bled into  four  or  five  anastomosing  trunks;  which  envelop  the 
vas  deferens  and  the  spermatic  artery,  and  compose  a  principal 
part  of  the  bulk  of  the  chord.  Having  passed  through  the 
abdominal  canal,  they  are  reduced  on  each  side  to  one  trunk, 
which  creeps  along  the  spermatic  artery,  on  the  front  of  the 
psoas  magnus  muscle,  and  in  company  with  the  ureter.  Some- 
what below  the  kidney,  the  spermatic  vein  is  again  resolved 
into  a  sort  of  plexus,  having  frequent  additions  from  the  veins 
in  the  adipose  substance  of  the  kidney,  and  also  some  from  the 
branches  of  the  vena  portarum  in  the  mesentery,  and  in  the 
mesocolon.  It  then  is  reduced  once  more  into  a  single  trunk, 
which  terminates  as  mentioned.  The  term  Corpus  Pampini- 
forme  (vine-like)  is5  by  some  anatomists,  limited  to  the  last 


268  CIRCULATORY  SYSTEM. 

plexus  formed  by  each  spermatic  vein,  but  it  is  also  frequently 
extended  to  both.* 

In  the  female,  the  spermatic  vein  is  not  so  large  as  in  the 
male;  it  "comes  from  the  ovarium  and  from  the  side  of  the 
uterus,  and  is  joined  by'some  small  branches  from  the  round 
ligament  of  the  uterus,  and  from  the  Fallopian  tube.  Passing 
outwardly  between  the  laminae  of  the  broad  ligament  of  the 
uterus,  it  crosses  the  external  iliac  artery,  and  in  the  subse- 
quent part  of  its  course  is  disposed  of  as  in  the  male. 

The  Emulgent  Veins  (Venss  Emulgentes,  Renales}  are 
commonly  two  in  pumber,  one  on  each  side,  and  extend  ho- 
rizontally from  the  fissure  of  the  kidneys  to  the  ascending 
cava.  They  are  of  a  considerable  size,  and  owing  to  the 
position  of  the  vena  cava,  the  left  is  much  longer  than  the 
right,  and  crosses  in  front  of  the  aorta.  They  open  on  their 
respective  sides  of  the  cava  opposite  to  each  other.  The 
branches  of  which  the  emulgent  vein  is  composed,  coming 
From  the  ramifications  of  the  corresponding  artery  in  the 
kidney,  assemble  into  the  single  trunk  near  the  fissure  of  the 
kidney;  this  trunk  is  joined  by  some  small  veins  from  the 
adjacent  adipose  matter  and  from  the  capsulae  renales,  and 
on  the  left  side,  as  mentioned,  it  is  also  joined  by  the  sper- 
matic vein. 

The  Capsular  Veins  (Venae  Capsulares)  arise  from  the 
arteries  spent  upon  the  capsule  renales;  and  are  two  in  num- 
ber, one  on  each  side.  That  on  the  right  discharges  into  the 
vena  cava,  while  the  one  on  the  left  empties  into  the  left 
emulgent  frequently. 


Hepatic  Veins  (Vena  Hepaticce)  take  their  rise  in 
the  liver,  and  collect  into  three  principal  trunks,  which  con- 
verging towards  the  ascending  cava,  discharge  themselves 
into  it,  where  it  adheres  to  the  posterior  margin  of  the  liver, 
immediately  below  the  diaphragm.  Two  of  these  trunks 
<come  from  the  right  lobe,  and  one  from  the  left,  moreover, 

*  H.  Ctoquet,  Trait.  D'Anat. 


OP  THE  VENA  PORTARUM.  269 

there  are"  several  small  hepatic  veins  which  discharge  them- 
selves into  the  cava,  and  come  principally  from  the  Lobulus 
Spigelii. 

The  Inferior  Phrenic  Veins  ( Fence  Phrenicce  Inferiores)  come 
from  the  diaphragm,  from  the  corresponding  arteries.  They  are 
two  in  number,  and  discharge  into  the  ascending  cava  just  above 
the  hepatic  veins. 

SECT.  V. — OF  THE  VENA  PORTARUM.    * 

The  Vena  Portarum  is  derived  from  the  viscera  of  the  abdo- 
men, and  presents  the  singularity  of  a  vein  ramifying  through  a 
gland,  the  liver,  before  its  blood  is  returned  to  the  general  circu- 
lation. The  arteries  from  which  it  draws  its  supply  of  blood  are 
the  superior  and  the  inferior  mesenteric,  and  the  coeliac  with  the 
exception  of  its  hepatic  branch.  The  viscera  of  the  abdomen, 
which  contribute  to  it  are  the  spleen,  the  gall-bladder,  the  pan- 
creas, the  stomach,  the  small  and  large  intestines,  and  the  large 
and  the  small  omentum. 

a.  The  Splenic  Vein  (Vena  Splenica)  is  formed  by  several 
branches,  which  coming  out  distinctly  from  the  fissure  of  the 
spleen,  unite  after  a  short  course  into  a  single  trunk.  This  trunk 
runs  in  company  with  the  splenic  artery  below  it,  along  the  su- 
perior margin  of  the  pancreas,  is. not  quite  so  tortuous  as  the*  ar- 
tery itself,  and  proceeding  from  left  to  right,  is  joined  to  the  su- 
perior mesenteric  vein  in  front  of  the  vertebral  column. 

In  this  course,  the  splenic  receives  the  small  veins,*  (Fence 
Breves,)  corresponding  with  the  vasa  brevia  of  the  great  end  of 
the  stomach,  and  then,  successively,  several  branches  from  the 
pancreas.  It  likewise  receives  the  gastric,  or  the  superior  coro- 
nary vein  of  the  stomach,  the  right  gastro-epiploic,  and  the  left 
gastro-epiploic  of  the  same  viscus,  all  of  which  correspond  with 
the  arteries  distributed  to  the  latter. 

b.  The  Inferior  Mesenteric  Vein  ( Vena  Meseraica  Inferior)  cor- 

•  M.  Bauer  discovered,  in  1824,  valves  in  these  vessels,  contrary  to  the  gene- 
ral analogy  of  the  system  of  the  Vena  Portarum.  His  observations  have  been 
confirmed  by  H.  Cloquet. 

VOL.  II.— 35 


270  CIRCULATORY  SYSTEM. 

responds  with  the  inferior  mesenferic  artery,  and,  consequently, 
derives  its  primitive  branches  from  the  rectum  by  the  upper  he- 
morrhoidal  veins,  which  anastomose  with  the  lower;  from  the 
sigmoid  flexure  of  the  colon,  and  from  the  left  descending  por- 
tion of  the  latter.  The  trunk  formed  by  these  branches,  ascends 
behind  the  peritoneum,  between  the  ureter  and  the  aorta ;  and 
going  up  behind  the  pancreas,  is  discharged  into  the  splenic  vein 
an  inch  or  two  from  its  termination.  But,  like  the  veins  belong- 
ing to  the  lesser  curvature,  and  the  right  side  of  the  stomach, 
it  sometimes  empties  directly  into  the  vena  portarum,  or  into  the 
upper  end  of  the  superior  mesenteric. 

c.  The  Superior  Mesenteric  Vein  ( Vena  Meseraica  Superior)  is 
the  largest  of  the  trunks  which  contribute  to  form  the  vena  por- 
tarum. It  is  derived  from  the  ramifications  of  the  superior  me- 
senteric artery  upon  the  small  intestines,  the  ileo-colic  valve,  the 
right  ascending  and  the  transverse  colon.  Its  branches  consti- 
tute in  the  mesentery  and  the  mesocolon  a  vascular  intertexture, 
forming  arches  and  meshes  adhering  to  the  corresponding  ones 
of  the  arteries.  In  the  transverse  mesocolon,  it,  like  the  artery, 
anastomoses  with  the  inferior  mesenteric  vein.  Its  trunk  being 
formed  by  the  union  of  these  several  branches,  ascends  the  me- 
sentery, and  goes  in  front  of  the  duodenum,  where  the  latter 
crosses  the  spine ;  immediately  afterwards  it  gets  behind  the  pan- 
creas, and  near  its  right  end  is  joined  by  the  splenic  vein.  It 
here,  also,  receives  small  branches  from  the  duodenum,  from  the 
pylorus,  and  from  the  gall-bladder. 

/  The  trunk  of  the  Vena  Portarum  being  formed  behind  the  pan- 
creas by  the  union  of  the  superior  mesenteric  with  the  splenic 
vein,  extends  from  this  point  to  the  transverse  fissure  of  the  liver, 
and  is  about  four  inches  in  length.  It  ascends  obliquely  from  left 
to  right,  behind  the  second  curvature  of  the  duodenum,  being 
bounded  on  the  right  side  by  the  biliary  ducts,  and  on  the  left 
by  the  hepatic  artery,  where  it  is  surrounded  by  a  great  many 
nervous  filaments  and  lymphatic  vessels,  with  aU  of  which  it  is 
united  by  a  common  envelope  of  cellular  substance,  and  of  peri- 
toneum, called  the  capsule  of  Glisson.  Having  reached  the 
transverse  fissure  of  the  liver,  it  divides  into  two  branches,  which 


PECULIARITIES  OF  THE  FCETUS.  271 

are  each  at  a  right  angle  to  it,  but  in  line  with  one  another:  they 
constitute  the  Sinus  Portarum,  of  which  the  right  branch  being 
spent  upon  the  great  lobe,  and  the  left  upon  the  small  lobe  of  the 
liver,  are  ramified  almost  to  infinity  through  the  structure  of  the 
latter.  The  terminating  branches  of  the  vena  portarum  empty 
into  the  venae  hepaticae. 

Several  cases  are  recorded  in  the  annals  of  anatomy  in  which 
the  vena  portarum,  instead  of  going  into  the  liver,  discharged 
immediately  into  the  ascending  cava.*  In  such  instances  the 
hepatic  artery  is  much  larger  than  usual.  According  to  J.  F. 
Meckel,  notwithstanding  they  are  anomalies,  yet,  as  in  most  other 
cases  of  deviation  from  the  general  type  of  the  human  family,  a 
striking  analogy  may  be  found  between  them  and  what  occurs 
in  some  of  the  lower  orders  of  animals.  Here  the  analogy  ex- 
ists with  the  invertebrated  animals. 


CHAPTER  IV. 


OF  THE  PECULIARITIES  IN  THE  CIRCULATORY  SYSTEM  OF  THE 

FOZTUS. 

OWING  to  the  want  of  respiration  in  the  foetus,  its  circulation 
is  conducted  in  a  manner  very  different  from  that  of  the  adult. 
Moreover,  its  parasitical  life  requires  an  alliance,  through  the 
organs  of  circulation,  with  the  mother.  Its  peculiarities,  there- 
fore, may  be  studied  under  two  heads :  those  which  arise  from 
the  want  of  respiration,  and  those  which  are  required  for  its 
nourishment.  The  peculiarities  of  the  first  order  are  situated  in 
the  thorax,  and  those  of  the  second  in  the  abdomen. 

*  Lieutaud,  Hist.  Anat.  Med.  Huber,  Obs.  Anat.  p.  34.  Abernethy,  Ph.  Tr. 
1793,  pai't  i.  Lawrence,  Med.  Ch.  Trans,  vol.  v. 


272  CIRCULATORY  SYSTEM. 


SECT.  I. OF   THE   PECULIARITIES  OF   THE  FffiTUS,  ARISING  FROM  THE 

WANT  OF  RESPIRATION. 

The  Heart,  at  a  very  short  period  after  conception,  so  early 
as  about  the  end  of  the  first  month,  is  sufficiently  developed  to 
be  in  a  state  of  great  activity.  The  first  indication  of  its  exist- 
ence, and,  indeed,  of  the  life  of  the  new  animal,  is  a  small  tre- 
mulous point,  called  the  Punctum  Saliens,  from  its  incessant  mo- 
tion. The  muscular  structure  of  it  is  soon  evolved,  and  in  a 
few  weeks  becomes  very  manifest.  At  the  earliest  visible  pe- 
riod of  the  heart  in  the  incubated  egg,  which  affords  a  satisfac- 
tory analogy,  it  consists  of  two  vesicles  united  by  a  canal,  (Ca- 
nalis  Auricularis  of  Haller.)  One  of  the  vesicles  is  the  right 
auricle ;  the  other  is  the  left  ventricle,  and  is  probably  the  first 
to  pulsate.  The  aorta  is  also  visible,  as  well  as  the  venae  cavae. 
The  circulation,  at  this  period,  is  very  simple:  the  blood,  start- 
ing from  the  left  ventricle,  is  propelled  into  the  aorta ;  it  is  col- 
lected from  the  ramifications  of  the  last  into  the  two  venae  cavas, 
and  thereby  brought  to  the  right  auricle;  it  is  then  propelled  by 
the  right  auricle  through  the  canalis  auricularis  into  the  left 
ventricle,  whereby  its  round  is  completed,  and  it  then  starts 
again.  This  is  the  most  simple  kind  of  circulation,  and  is  found, 
in  fact,  during  the  whole  lives  of  such  animals  as  do  not  breathe 
by  lungs ;  for  example,  fish.  As  the  gills  in  them  take  the  place 
of  lungs,  a  branch  from  the  aorta,  spent  upon  the  gills,  is  suffi- 
cient for  their  purposes  of  respiration. 

The  terms  right  auricle  and  left  ventricle  have  been  used,  be- 
cause the  cavities  alluded  to  perform  the  functions  of  the  adult 
state;  but  in  the  progress  of  the  development  of  the  heart,  a  par- 
tition begins  to  show  itself  which  ultimately  divides  each  of  them 
into  two  distinct  compartments,  whereby  we  have  a  right  auricle 
and  a  left  one,  a  left  ventricle  and  a  right  one.  And  the  canalis 
auricularis  is  reduced  from  a  canal  into  a  short  orifice,  called 
Ostium  Venosum,  communicating  from  the  auricles  to  the  ven- 
tricles, and  which  is  afterwards  divided  into  two,  one  for  either 
side  of  the  heart.  The  partition  between  the  ventricles  is  com- 
pleted about  the  end  of  the  second  month  of  gestation,  at  a  period 
when  the  aorta,  from  having  been  simple  originally,  is  converted 


PECULIARITIES  OF  THE  FffiTUS.  273 

into  two  canals,  one  of  which  becomes  the  pulmonary  artery. 
The  partition  between  the  auricles  is  not  completed  till  birth. 
In  cases  of  monstrosity,  it  is  interesting  to  see  how  much  the 
heart,  at  the  end  of  uterine  life,  has  still  preserved  this  origi- 
nal type  of  simplicity.  I  have  lately  dissected  a  double  foetus, 
where,  from  the  parasitical  character  of  one,  no  effort  had  been 
made  for  the  development  of  the  lungs  of  the  latter.  The  con- 
sequence of  which  was,  the  parasite's  heart  consisted  only  of  the 
right  auricle  and  of  the  left  ventricle,  and  the  pulmonary  artery 
had  not  been  formed  at  all,  there  being  but  the  single  tube,  the 
aorta,  which  led  from  the  left  ventricle,  and  had  a  sort  of  arrange- 
ment in  its  branches  depending  upon  the  tendency  to  form  pul- 
monary arteries.* 

At  birth,  the  auricular  septum  has  advanced  so  far  that  the 
communication  between  the  two  cavities  is  kept  up  only  by  a 
deficiency,  called  the  Foramen  Ovale.  This  foramen,  marked 
by  a  depression  on  the  right  side,  admits  a  small  quill,  when  con- 
ducted obliquely  through  it,  and  is  protected  on  the  left  side  by 
a  valve,  the  edge  of  which  is  upwards,  and  which,  when  applied, 
is  just  large  enough  to  cover  the  whole  foramen.  The  moment 
that  the  blood  ceases  to  pass  through  the  foramen  ovale,  which 
occurs  at  the  first  act  of  inspiration,  the  valve  is  applied,  and 
the  aperture  grows  up  by  the  adhesion  of  its  edge.  The  me- 
chanism of  this  process  is  sufficiently  simple.  So  long  as  the 
principal  current  of  blood  was  into  the  right  auricle,  the  valve 
was  pushed  off  from  the  side  of  the  septum ;  but  as  breathing 
establishes,  through  the  lungs,  pulmonary  veins,  and  left  auricle, 
a  current  of  circulation  equivalent,  both  in  quantity  and  force,  to 
that  through  the  two  venae  cavae  and  right  auricle,  a  perfect 
equilibrium  between  the  auricles  is  established,  and  the  valve  re- 
tains its  place  against  the  septum.  Notwithstanding  the  inces- 
sant action  of  the  auricles,  during  all  the  subsequent  periods  of 
life,  this  equilibrium,  in  the  force  and  time  of  their  contraction, 
remains  uniform:  a  circumstance  proved,  conclusively,  by  the 
health  and  strength  of  adults  in  whom  the  valve  has  never  ad- 
hered to  the  day  of  their  death;  an  observation  made  by  many 


*  For  a  detail  of  this.case,  see  North  American  Medical  and  Surgical  Journal, 
Philad.  Oct.  1826. 


274  CIRCULATORY  SYSTEM. 

anatomists,  and  of  which  I  have  witnessed  several  examples.  In 
one  of  them  I  passed  two  fingers  readily  from  one  auricle  into 
the  other,  owing  to  the  unusual  size  of  the  aperture. 

The  valve  which  closes  the  foramen  ovale  is,  first  of  all, 
scarcely  perceptible ;  but  as  the  foetus  advances  in  age,  it  also  ad- 
vances in  size,  and  is,  indeed,  large  enough  to  close  the  foramen 
some  weeks  before  birth.  It  is  formed  from  the  lining  mem- 
brane of  the  two  auricles,  with  some  intermediate  substance. 

The  Valve  of  Eustachius,  which  exists  also  in  the  adult  heart, 
is  placed  at  the  anterior  semi-circumference  of  the  orifice  of  the 
ascending  vena  cava  in  the  right  auricle,  one  of  its  ends  ad- 
hering to  the  anterior  margin  of  the  foramen  ovale.  This  valve, 
contrary  to  the  one  in  the  foramen  ovale,  is  larger  in  proportion 
as  the  foetus  is  younger,  and,  when  first  observed,  covers  the 
whole  orifice  of  the  vena  cava  ascendens ;  its  opening,  however, 
is  in  the  direction  of  the  current  of  blood  in  the  latter.  It  also  is 
formed  by  a  duplicature  of  the  lining  membrane  of  the  auricle ; 
and,  from  its  disposition,  determines  the  blood  of  the  ascending 
cava  to  flow  through  the  foramen  ovale  into  the  left  auricle,  ei- 
ther wholly  or  in  part,  according  to  the  period  of  gestation.  Its 
obliquity  also  gives  a  direction  to  the  blood  of  the  descending 
cava,  into  the  right  ventricle  from  the  right  auricle.  These 
uses  of  the  Eustachian  valve  were  pointed  out  by  the  celebrated 
Sabatier  :*  their  value  will  be  illustrated  hereafter. 

The  Ventricles  of  the  Heart,  at  birth,  have  the  same  structure 
and  internal  arrangement  as  afterwards ;  they  are  remarkable, 
however,  for  being  of  equal  thickness,  or  nearly  so,  an  observa- 
tion of  Mr.  John  Hunter.t  This  fact  is  connected  with  the  cir- 
cumstance of  their  both  contributing  to  the  aortic  circulation  till 
respiration  begins,  owing  to  the  pulmonary  artery  entering, 
during  foetal  life,  by  its  largest  branch,  into  the  aorta. 

The  Ductus  Arteriosus  constitutes  this  branch  of  the  pulmo- 
nary artery,  and  is,  in  fact,  the  continuation  of  the  trunk  of  the 
latter  into  the  aorta,  immediately  behind  the  origin  of  the  left 

*  Traite  d'Anat.  vol.  ii,  p.  296. 
f  Animal  (Economy. 


PECULIARITIES  OF  THE  FffiTUS.  275 

subclavian  artery.  The  right  and  the  left  pulmonary  arteries, 
at  this  period,  are  but  inconsiderable  trunks,  incapable  by  any 
means  of  carrying  off  all  the  blood  of  the  right  ventricle ;  the 
greater  part  of  it,  therefore,  is  conveyed  by  the  ductus  arteriosus 
into  the  descending  aorta.  As  the  contraction  of  the  ventricles, 
like  that  of  the  auricles,  is  synchronous,  it  is  evident  that  the 
column  of  blood  in  the  descending  aorta,  is  acted  upon  by  both 
ventricles  at  the  same  moment. 

The  ductus  arteriosus,  preserves  the  principle  of  a  single  cir- 
culation in  the  foetus ;  which  was  first  of  all  manifested  by  the 
two  ventricles,  constituting  but  one  cavity ;  and  by  the  aorta 
and  pulmonary  artery  being  but  one  trunk.  At  the  first  act  of 
inspiration  the  lungs,  which  were  before  solid,  and  the  thorax, 
which  was  compressed,  are  greatly  augmented  in  volume  by 
the  introduction  of  air.  The  dilatation  of  the  thorax,  besides 
introducing  air  through  the  trachea,  causes  an  increased  flow  of 
blood  through  the  right  and  left  pulmonary  arteries,  in  order  to 
fill  the  vacuum  in  the  lungs.  The  pulmonary  arteries  become 
in  that  way  permanently  dilated,  and  the  circulation  is  finally 
drawn  off  entirely  from  the  ductus  arteriosus,  though  this  takes 
several  weeks  or  months  before  it  is  completely  accomplished. 
The  ductus  arteriosus  in  this  time  is  continually  contracting,  and 
is  at  length  converted  into  a  ligamentous  chord,  like  other  ar- 
teries, whose  circulation  has  been  arrested. 

These  are  the  several  peculiarities  which  distinguish  the  foetal 
circulation,  owing  to  the  privation  of  respiration ;  and  it  is  clear, 
that  the  collective  result  is  that  of  a  circulation  quite  as  simple 
as  if  the  heart  consisted  of  but  two  cavities ;  while,  at  the  same 
time,  it  keeps  this  organ  in  a  state  of  preparation  for  carrying 
on  two  distinct  circulations,  one  pulmonary  and  the  other  aortic, 
from  the  moment  that  respiration  begins;  so  that  the  whole 
mass  of  blood  is,  in  subsequent  life,  brought  successively  under 
the  influence  of  respiration,  by  having  to  pass  unavoidably 
through  the  lungs. 


276  CIRCULATORY  SYSTEM. 

SECT.  II. — OF    THE    PECULIARITIES    OF    THE    CIRCULATION    OF    THE 
FCETUS  CONNECTED  WITH  ITS  NOURISHMENT. 

The  Umbilical  Vein,  one  of  the  constituents  of  the  umbilical 
chord,  .brings  the  blood  from  the  placenta  to  the  foetus.  This 
vessel  is  from  three  to  four  lines  in  diameter,  and  enters  at  the 
navel ;  thence  it  goes  along  the  loose  margin  of  the  suspensory 
ligament  of  the  liver,  and  traverses  the  anterior  half  of  the  um- 
bilical fissure,  to  terminate  in  the  left  branch  of  the  sinus  of 
the  vena  portarum.  In  this  course  through  the  liver,  the  umbi- 
lical vein  sends  off  to  the  right  and  left  lobes,  several  small 
branches.  As  the  intestinal  circulation  of  the  foetus  is  too  small 
to  send  much  blood  through  the  vena  portarum,  it  would  be  suf- 
ficiently correct  to  consider  the  sinus  venag  portarum  as  the  bi- 
furcation of  the  umbilical  vein ;  but,  as  this  might  introduce  a 
confusion  into  the  description,  it  will  be  better  to  retain  the  adult 
nomenclature. 

The  Ductus  Venosus  is  a  vein  which  occupies  the  posterior 
half  of  the  umbilical  fissure,  and  is  about  a  line  and  a  half  in 
diameter.  It  arises  from  the  left  branch  of  the  sinus  portarum, 
opposite  to  the  place  where  the  umbilical  vein  entered  or  termi- 
nated, and  is  consequently  in  the  same  line  with  the  latter. 
Traversing  the  posterior  part  of  the  umbilical  -fissure,  it  termi- 
nates in  the  left  vena  cava  hepatica,  as  this  vein  is  about  joining 
the  ascending  cava,  just  below  the  tendinous  centre  of  the  dia- 
phragm. Through  this  route  much  of  the  blood  of  the  umbili- 
cal vein  is  carried  directly  to  the  right  auricle  of  the  heart,  and 
then  passed  through  the  foramen  ovale  into  the  left  auricle  by 
the  mechanism  of  the  Eustachian  valve. 

From  these  considerations,  it  is  evident  that  the  umbilical 
vein  really  performs  the  office  of  a  vein  till  it  reaches  the  liver, 
but  that  there  much  of  its  blood  is  spent  through  the  portal  cir- 
culation, upon  the  nourishment  of  this  viscus,  and  that  what  re- 
mains is  carried  through  the  ductus  venosus  to  the  heart.  Like 
other  veins,  it  is  furnished  with  valves,  of  which  there  are  two: 
one  at  its  termination  in  the  sinus  portarum,  and  the  other  at  the 


PECULIARITIES  OF  THE  IXETUS.  277 

cardiac  extremity  of  the  ductus  venosus.*  The  establishment 
of  respiration,  by  putting  the  circulation  into  other  channels, 
likewise  causes  its  obliteration  and  final  conversion  into  a  liga- 
mentous  chord.  The  valve,  at  the  sinus  portarum,  prevents  the 
blood  from  taking  a  retrograde  course,  and  thereby  keeping  the 
umbilical  vein  open ;  the  valve  of  the  ductus  venosus  has  the 
same  effect  upon  the  duct  to  which  it  belongs,  and  is  aided  by 
the  current  of  blood  in  the  left  branch  of  the  sinus  portarum, 
setting  across  the  mouth  of  the  ductus  venosus  instead  of 
plunging  into  it  from  the  umbilical  vein,  as  in  foetal  life. 

It  is  worthy  of  remark,  that  the  left  branch  of  the  sinus  por- 
tarum is  bounded,  on  its  right  extremity,  by  the  end  of  the  vena 
portarum,  and  receives,  about  its  middle,  the  umbilical  vein.  In 
the  space,  then,  between  the  umbilical  vein  and  the  portal,  the 
circulation,  from  the  predominance  of  umbilical  blood  in  foetal 
life,  is  conducted  from  left  to  right,  but  afterwards  from  right 
to  left,  as  the  portal  circulation  is  established  and  the  other  is 
arrested. 

The  Umbilical  Arteries  discharge  the  important  office  of  con- 
ducting the  effete  blood  of  the  foetus  to  the  placenta.  They  are 
the  continuations  of  the  internal  iliacs,  and  are  two  in  number, 
one  on  either  side ;  they  conduct  off  so  much  of  the  blood  of  the 
primitive  iliac:,  as  to  leave  the  external  iliacs  of  a  very  small 
size.  During  the  early  months  of  uterine  life,  they  are  rather, 
indeed,  the  continued  trunks  of  the  primitive  iliacs,  the  branches 
from  the  latter  being  then  so  little  developed  as  to  appear  quite 
subordinate  to  the  chief  function  of  carrying  the  blood  out  of 
the  foetus  to  the  placenta.  But  as  the  inferior  extremities  and 
the  buttocks  grow,  these  subordinate  branches  are  more  and 
more  evolved. 

At  birth,  the  umbilical  arteries,  after  dipping  very  superficially 
into  the  pelvis,  rise  up  at  the  sides  of  the  bladder  and  converge 
towards  the  navel.  They  emerge  at  the  latter,  cling  together 
and  traverse  the  umbilical  chord  by  twisting  spirally  around  the 
umbilical  vein,  like  two  small  strings  wound  in  this  way  upon  a 

*  Bichat,  Anat,  Descrip.  vol.  v.  p.  419. 
VOL.  II.— 36 


278  CIRCULATORY  SYSTEM. 

larger  one.  Their  diameter  is  from  a  line  to  a  line  and  a  half. 
They  anastomose  as  they  join  the  placenta,  but  not  previously. 

Like  the  circulation  between  arteries  and  veins  in  other  parts 
of  the  body,  the  capillaries  of  the  umbilical  arteries  terminate  in 
those  of  the  umbilical  vein  in  the  placenta.  From  the  observa- 
tions of  Wrisberg,  Osiander,  and  the  highly  distinguished  Pro- 
fessor Chapman  of  the  University  of  Pennsylvania,  it  seems  that 
there  is  no  direct  vascular  communication  between  the  mother 
and  the  foetus. 

This  opinion  is  founded  upon  the  leading  facts,  that  the  finest 
injections  do  not  pass  from  one  to  the  other;  that  foetuses,  after 
the  death  of  the  mother  from  haemorrhage,  still  live  and  retain 
their  usual  quantity  of  blood ;  that  if  the  foetus  be  expelled  entire 
with  the  placenta,  and  membranes  unhurt,  the  circulation  still 
continues.  One  example  of  which  was  witnessed  nine  minutes 
by  Wrisberg;*  another  fifteen  by  Osiander ;f  some  from  ten  to 
twenty  minutes  by  Professor  Chapman  ;J  another  for  an  hour 
by  Professor  Channing  of  Boston,  and  Dr.  Selby  of  Tennessee,§ 
where  a  bath  of  tepid  water  was  used  to  resuscitate  the  foetus. 
Also,  from  the  observations  of  Breschet,  it  seems  that  the  glo- 
bules of  the  blood  of  the  foetus,  when  inspected  by  the  micro- 
scope, are  different  in  appearance  from  those  of  the  mother.  || 

Mascagni  says  that  he  has  made  several  most  minute  injec- 
tions of  the  pregnant  uterus,  so  as* to  cover  with  small  vessels 
its  whole  internal  surface,  and  to  return  the  injection  by  the  ute- 
rine veins :  and  yet  he  has  never  succeeded  in  injecting,  in  that 
way,  the  secundines.lf 

I  have,  myself,  repeatedly  tried  by  minute  injection  to  pass 
articles  from  the  fnetal  into  the  maternal  vessels,  and  the  re- 
verse, but  always  without  success ;  in  two  instances,  the  experi- 
ment was  upon  human  subjects,  and,  in  the  others,  on  the  cow. 
In  one  of  the  latter,  I  perceived  that  some  of  the  injecting  mat- 
ter thrown  into  the  foetal  vessels  had  got  into  the  uterine  veins ; 
but  as  the  observation  was  in  opposition  to  all  my  others,  and 
solitary,  I  have  felt  no  disposition  to  array  it  against  them,  at 

*  Meckel,  Man.  D'Anat.  vol.  iii.  p.  1G3.  f  Id. 

t  Chapman's  Mcd.  and  Phys.  Journal,  vol.  i.  p.  6.  .  §  Id. 

||  Am.  Mcd.  Jour.  vol.  5.  p.  193. 
^  Prodromo,  vol.  i.  p.  127. 


PECULIARITIES  OF  THE  FffiTUS.  279 

least,  until  farther  and  more  decided  experience.  My  second  ex- 
periment on  the  human  subject  was  made  in  April,  1833,  under 
the  following  circumstances :  A  white  female,  aged  24,  died  at 
the  Alms  House,  suddenly,  and  in  the  ninth  month  of  pregnancy, 
the  foetus  was  still  in  utero,  but  the  membranes  were  ruptured. 
In  the  presence  of  several  of  the  physicians  and  students,  and 
with  the  assistance  of  my  young  friend,  Dr.  Goddard,  to  whose 
suggestions  and  manipulations  I  am  indebted  for  the  chemical 
compounds  resorted  to.  I  injected  through  the  aorta  one  gallon 
of  the  saturated  solution  of  Prussiate  of  potash,  and  followed  it 
with  an  equal  quantity  of  a  saturated  solution  of  sulphate  of  iron. 
The  injection  penetrated  very  minutely,  as  might  be  expected, 
and  the  precipitate  of  Prussian  blue  coloured  deeply  many*parts 
of  the  skin.  On  dissecting  the  uterus,  the  uterine  arteries  were 
found  well  injected,  but  the  injection  did  not  reach  the  umbilical 
vein  or  arteries,  as  was  proved  both  by  simple  inspection  and  by 
chemical  test. 

Having  cut  out  the  uterus  and  taken  it  to  the  University,  the 
experiment  was  continued  the  next  day  in  the  presence  of  a  large 
concourse  of  students  and  several  physicians.  The  umbilical 
vessels  were  first  of  all  injected  with  a  saturated  solution  of  bi- 
chromate of  potash,  and  then  with  a  saturated  solution  of  sugar 
of  lead,  the  result  was  a  strong  yellow  precipitate,  the  bichro- 
mate of  lead.  The  injection  passed  reciprocally  from  the  arte- 
ries into  the  vein,  or  from  the  vein  into  the  arteries,  conforma- 
bly to  the  direction  in  which  it  was  thrown  for  the  time.  The 
sinuses  of  the  uterus  were  then  injected  with  similar  materials 
to  those  of  the  uterine  arteries ;  to  wit,  a  solution  of  Prussiate  of 
potash,  followed  by  one  of  sulphate  of  iron. 

The  umbilical  vessels  were  then  all  filled  with  liquid  plaster  of 
Paris  coloured  yellow ;  and  the  uterine  sinuses  with  liquid  plas- 
ter of  Paris  coloured  blue,  of  which  they  readily  received  eigh- 
teen ounces.  A  short  time  having  been  allowed  for  the  setting 
of  the  injection,  I  cut  into  the  substance  of  the  uterus  and  of  the 
placenta.  No  yellow  injection  was  found  in  the  vessels  of  the 
uterus,  nor  was  there  any  blue  injection  found  in  the  umbilical 
vessels  of  the  placenta ;  there  was,  therefore,  a  deficiency  of  evi- 
dence of  direct  vascular  communication  between  the  fcetus  and 
the  mother.  The  placenta  was  infiltrated  with  Prussiate  of  iron, 


280  CIRCULATORY  SYSTEM. 

and  considerable  quantities  of  blue  plaster  were  found  in  the  ca- 
vity of  the  uterus. 

In  the  progress  of  the  injection  with  the  Prussiate  of  iron,  into 
the  uterine  sinuses,  the  membranes  were  raised  from  the  uterus 
in  vesications. 

The  parts  having  been  distended  and  put  aside  to  dry,  at  the 
end  of  a  fortnight  they  were  examined  again  by  incisions,  and 
the  same  evidence  of  the  want  of  direct  vascular  communication 
was  renewed.  But  the  placenta  was  found  to  be  infiltrated  ac- 
cording to  certain  rules  seeming  to  depend  on  its  organization. 
The  blue  colouring  matter  on  the  part  of  the  uterus,  and  the 
yellow  on  the  part  of  the  fetus,  determined  in  it  two  parts,  one 
uteriie  and  the  other  fetal,  closely  and  alternately  interlocked, 
like  a  dove-tailing :  the  uterine  processes  passed  to  within  a  short 
distance  of  the  free  surface  of  the  placenta,  while  the  foetal  pro- 
cesses went  almost  to  the  base  of  the  placenta.  The  confines  of 
the  two  colours  were  defined  well  by  this  abrupt  termination,  the 
borders  of  these  dove-tails.  The  appearance  would,  perhaps,  be 
better  designated  by  the  terms  uterine  lobes,  and  fetal  lobes, 
alternately  penetrating,  so  as  to  constitute  the  whole  mass  of  the 
placenta.  No  distinct  vessel  of  a  blue  colour  could,  however,  be 
seen  in  the  uterine  lobes,  but  a  few  very  sparse  yellow  ones  were 
visible.  On  raising  up  these  uterine  divisions,  the  orifices  of  the 
uterine  sinuses  were  seen  at  their  base. 

The  inference  from  this  experiment  is,  that  though  there  is  no 
direct  connexion  of  blood  vessels  between  the  mother  and  the 
foetus,  yet  there  is  a  part  of  the  placenta  which  seems  to  bold  a 
special  connexion  with  the  uterine  sinuses,  and  which  may  pos- 
sibly, therefore,  by  interstitial  circulation,  establish  a  connexion 
with  the  fetus.  The  facts  are  at  any  rate  presented  as  they 
occurred. 

The  effete  blood  of  the  umbUical  arteries  becomes  regenerated 
in  the  placenta,  assumes  a  brighter  hue,  and  is  returned  to  the 
foetus  by  the  umbilical  vein.  According  to  the  theory  of  Saba- 
tier  concerning  the  use  of  the  Eustachian  valve,  if  the  latter 
diti.  not  exist,  the  fresh  blood  brought  to  the  heart  by  the 
ductus  venosus,  instead  of  being  diverted  into  the  left  auricle 
through  the  foramen  ovale,  would  be  received  by  the  right 
auricle,  and  transmitted,  either  wholly  or  in  a  great  degree,  into 


ANATOMY  OF  THE  ABSORBENT  SYSTEM.  281 

the  right  ventricle.  It  would  then  be  passed  from  the  latter 
through  the  pulmonary  artery  and  ductus  arteriosus  into  the  de- 
scending aorta,  so  that  no  part  of  the  system,  above  the  junction 
of  the  duct  with  the  aorta,  could  receive  the  benefit  of  it:  this 
would  leave  the  head  and  upper  extremities  unsupplied  with 
fresh  blood.  Moreover,  much  of  the  latter  would  be  fruitlessly 
introduced,  for  it  would  depart  almost  immediately  through  the 
umbilical  arteries.  But  the  Eustachian  valve  determining  the 
flow  of  blood  of  the  ascending  cava  into  the  left  auricle,  its  pas- 
sage into  the  left  ventricle  is  a  matter  of  course :  thence  it  be- 
gins the  aortic  circulation  fairly,  so  that  every  part  of  the  sys- 
tem participates  in  its  benefits. 

The  celebrated  Wistar*  has  also  happily  suggested,  that  with- 
out this  arrangement  the  blood  of  the  coronary  arteries  of  the 
heart  itself,  the  purity  of  which  is  so  essential  to  the  vigour  of 
circulation,  would  otherwise  have  been  effete,  and,  consequently, 
unfit  for  its  object  of  refreshing  the  heart. 

The  umbilical  arteries  become  the  round  ligaments  of  the 
bladder,  after  the  circulation  through  them  has  ceased,  with  the 
exception  of  their  pelvic  extremities,  which  subsequently  consti- 
tute the  trunks  of  the  Internal  Iliac  Arteries. 


CHAPTER  V. 


OF   THE  GENERAL  ANATOMY  OF  THE  ABSORBENT  SYSTEM. 

THE  absorbent  system  is  one  of  the  most  interesting  of  those 
which  compose  the  human  body,  both  on  account  of  its  very 
general  diffusion,  and  of  the  office  of  interstitial  absorption  that 
it  incessantly  carries  on,  thereby  removing  the  effete  parts  of 
the  body  and  making  room  for  the  deposite  of  new  ones.  It  is 
also  called  the  lymphatic  system,  owing  to  the  transparent  co- 
lour of  the  fluid  which  it  conducts. 

*  System  of  Anat.  vol.  ii.  p,  76,  3d  edition^ 


282  CIRCULATORY  SYSTEM. 

With  the  exception  of  an  imperfect  observation  of  some  of 
these  vessels  in  the  mesentery  of  a  goat,  by  Herophilus  and 
Erasistratus,  280  years  before  Christ,  during  the  reigns  of  the 
Ptolemies  in  Egypt,  what  is  known  of  them  is  entirely  a  modern 
acquisition  in  anatomy.  In  1564,  Eustachius  discovered  the  tho- 
racic duct  of  a  horse,  which,  in  the  ignorance  of  its  use,  he 
called  vena  alba  thoracis.  This  fact  remained  insulated  and 
almost  forgotten  for  seventy  years.  In  1622,  Asellius  disco- 
vered the  absorbents  of  the  mesentery,  and  in  the  discussions 
consequent  thereto,  the  original  observation  of  Herophilus  and 
Erasistratus  was  raised  from  an  oblivion  of  nineteen  centuries, 
to  be  again  brought  to  light  and  admired.  Asellius  seems  to 
have  understood  that  the  absorbents  of  the  mesentery  collect  the 
chyle  from  the  intestines,  but  his  knowledge  ceased  there,  for  he 
thought  that  they  discharged  into  the  vena  portarum.*  In  1634, 
Weslingius  saw  the  thoracic  duct  again;  and  in  1649,  ascer- 
tained that  the  chyliferous  vessels  of  Asellius  terminated  in  it. 
In  1650,  Olaus  Rudbeck,  a  young  man  pursuing  his  anatomical 
studies  in  Leyden,  saw  first  the  lymphatic  vessels  of  the  liver, 
and  in  a  few  months  afterwards  injected  similar  ones  in  the 
loins,  in  the  thorax,  in  the  groins,  and  in  the  arm-pits.  Thomas 
Bartholine,  a  teacher  of  great  reputation  in  those  days,  in  a  dis- 
sertation, dated  in  1652,  claimed  for  himself  the  priority  of  these 
observations,  and  from  the  obscurity  of  Rudbeck,  enjoyed  for 
some  time  the  merit  of  them.  In  1654,  Rudbeck  published  and 
set  forth  his  own  pretensions  with  such  force,  that  he  finally 
triumphed  over  his  antagonist,  but  not  until  the  whole  world  of 
anatomy  had  been  set  in  commotion ;  one  party  being  for  the 
professor,  and  the  other  for  the  pupil;  and  many  bloody  strifes 
having  arisen  between  the  students  of  the  respective  sides.  In 
1653,  Jolyff,  a  celebrated  anatomist,  of  London,  proclaimed  his 
own  rights  to  this  warmly  contested  honour;  but  the  period  be- 
ing rather  late,  his  name  is  scarcely  associated  with  the  history 
of  these  feuds.  Almost  a  century  then  passed  before  there  were 
many  important  additions  to  the  knowledge  of  those  times.  After 

*  It  is  somewhat  remarkable,  that  the  celebrated  Harvey,  who  had  himself  so 
much  to  complain  of,  in  the  obstinacy  with  which  his  cotemporaries  adhered  to 
ancient  errors,  for  thirty  years  resisted  the  discovery  of  Asellius,  and  died,  final- 
ly, protesting  against  it. 


ANATOMY  OF  THE  ABSORBENT  SYSTEM.  283 

which  great  contributions  were  made  by  Dr.  A.  Munro,*  Dr.  W. 
Hunter,f  Hewson,f  Cruikshank,§  but  chiefly  by  the  celebrated 
Mascagni,||  who,  having  imagined  finely  pointed  instruments  of 
glass  for  executing  his  injections  of  these  vessels,  succeeded  in 
demonstrating  them  in  almost  every  part  of  the  body,  excepting 
the  spinal  marrow,  the  brain,  the  ball  of  the  eye,  and  the  placen- 
ta. In  some  of  these  parts,  however,  he  says  he  has  seen  them, 
and  he  speaks  confidently  of  their  existence,  without  exception 
every  where,  even  in  the  enamel  of  the  teeth.1F 

The  Lymphatic  Vessels  are  small,  pellucid,  transparent,  cy- 
lindrical tubes,  generally  of  about  a  line  or  less  in  diameter, 
whose  trunks  have  been  traced  to  all  the  external  and  internal 
surfaces  of  the  body,  and  to  the  depth  of  all  the  organs,  with 
the  exceptions  stated.  It  is  only  very  lately,  however,  that  their 
existence  on  the  external  surface  of  the  skin  has  been  put  be- 
yond doubt,  by  the  observations  and  injections  of  M.  Lauth.** 
Their  origin  is  so  attenuated,  that  anatomists  have  come  to  no 
satisfactory  conclusion  in  regard  to  its  manner.  The  earlier 
cultivators  of  this  branch  of  study,  not  knowing  their  absorbent 
properties,  conceived  them  to  be  continuations  of  the  arteries 
applied  to  the  reconducting  of  the  serous  part  of  the  blood  to 
the  heart;  and  considered  the  opinion  substantiated  by  the  cir- 
cumstance of  their  being  occasionally  filled  by  fine  injections 
thrown  into  the  arteries.  More  improved  views  of  their  uses 
caused  the  abandonment  of  this  theory,  and  the  substitution  of 
their  absorbing  powers ;  in  which  case  the  minds  of  anatomists 
became  divided  between  the  ampulla-like  mouth,  or  wide  patu- 
lous  origin  of  Lieberkuhn,  and  the  small  orifices  of  Hewson. 
It  is,  perhaps,  not  possible  to  solve  the  question  in  regard  to  the 
mode  of  origin  of  the  lymphatics,  at  least,  in  most  parts  of  the 
body.  Meckel,  about  the  middle  of  the  last  century,  asserted 

*  De  Venis  Lymph.  Valv.  Berlin,  1757-70. 

f  Med.  Comment.  London,  1762-77. 

t  Experimental  Inquiries,  London,  1774-77. 

§  Anat.  of  the  Lymphatics,  London,  1774-90. 

II  Vasor  Lymph.  Corp.  Hum.  Historia  et  Ichnographia,  Sienne,  1787. 

11  Prodrome  della  Grande  Anatomia,  vol.  i.  p.  1. 

**  Essai  sur  les  Vaisseaux  Lymph.  Strasburg,  1824. 


284  CIRCULATORY  SYSTEM. 

their  continuity  with  the  veins.  Mr.  Ribes  has  seen  matter  in- 
jected into  the  vena  portarum  find  its  way  into  the  lymphatics 
of  the  liver. 

On  this  subject,  M.  Chaussier  says,*  that,  ignorant  of  the  man- 
ner in  which  the  arteries,  veins,  .nerves,  and  lymphatics,  arrange 
themselves  collectively  into  a  glandular  structure,  or,  in  other 
words,  into  a  capillary  system,  we  cannot  "avoid  ignorance  of 
the  part  acted  by  the  lymphatics  alone ;  we  only  know  that  the 
minute  lymphatics  form  a  portion  of  the  elements  of  each  viscus 
and  structure  of  the  body,  and  that  they  only  become  visihje  in 
becoming  larger  trunks. 

The  absorbents,  in  proceeding  from  their  origins,  in  general 
become  larger  and  less  numerous,  and  form  frequent  anastomoses 
with  one  another.  The  proportionate  increase  of  magnitude  from 
the  successive  junction  of  trunks  is,  however,  by  no  means  equal 
to  what  occurs  in  the  veins.  The  larger  superficial  absorbent 
trunks  of  the  extremities  have  not  so  much  disposition  to  run 
into  one  another,  whence  they  retain  a  size  almost  uniform  from 
one  end  of  the  limb  to  the  other.  When  fully  distended,  the  ap- 
pearance of  absorbents  is  not  regularly  cylindrical,  but  knotted, 
owing  to  the  frequent  valvular  interruptions  to  their  cavities. 
The  absorbents,  from  all  parts  of  the  body,  are  finally  united 
into  two  trunks ;  one  on  the  left,  and  the  other  on  the  right  side 
of  the  trunk  of  the  body,  and  which  discharge  their  contents  into 
the  venous  system,  each  on  its  respective  side,  at  the  junction  of 
the  internal  jugular  and  subclavian  vein.  The  trunk  on  the  right 
side  receives  the  lymphatics  of  the  right  side  of  the  head  and 
neck,  of  the  right  lung,  and  right  superior  extremity;  while  the 
trunk  on  the  left,  called  the  thoracic  duct,  receives  all  the  chyli- 
ferous  vessels  and  the  lymphatics  of  the  remaining  part  of  the 
body.  It  would  appear,  from  the  observations  of  the  younger 
Lauth,t  that  there  are  also  other  terminations  of  the  lymphatics 
in  the  veins;  to  wit,  such  as  in  the  yet  capillary  state  end  in  the 
veins  of  the  minute  structure  of  organs,  and  such  as  empty  into 
them  in  the  interior  of  the  lymphatic  glands.  Previously  to 
Lauth,  this  sentiment  of  communication  with  the  veins  was  strong- 

*  Diet,  des  Sciences  Med.  Art,  Lymphatiques.  - 

f  Loc.  cit. 


ANATOMY  OF  THE  ABSORBENT  SYSTEM.  285 

ly  advocated  by  several  anatomists  and  physiologists,  for  the  fol- 
lowing reasons:  1.  That  the  known  roots, of  the  lymphatic  sys- 
tem have  an  area  much  superior  to  that  of  the  trunks  in  which 
they  terminate.  2.  That  substances  introduced  into  certain 
lymphatics  by  absorption  or  injection,  have  been  found  in  the 
contiguous  veins.  3.  That  a  ligature  upon  the  thoracic  duct 
produced  death  only  after  ten  or  fifteen  days,  and  then  the  ar- 
ticles which  had  been  absorbed  by  the  intestines,  were  found  in 
the  blood.  4.  And  that  injections  had  proved  this  communica- 
tion. 

Notwithstanding  the  well  known  fact  of  injections,  under  cer- 
tain circumstances,  passing  from  the  arteries  into  the  lymphatics, 
some  anatomists  of  modern  date  have  hesitated  in  admitting  a 
direct  communication.  M.  Meckel  has,  indeed,  rejected  the  no- 
tion entirely,  on  the  ground  that  the  fluid  contained  in  the  trunks 
of  the  absorbents  is  always  the  same  as  one  finds  at  their  com- 
mencement. For  example,  the  lymphatics  coming  from  the 
liver  contain  a  fluid  like  bile ;  those  which  come  from  the  mammaB 
contain  a  fluid  like  milk;  those  which  come  from  parts  suffering 
from  an  extravasation  of  blood  contain  a  sanguineous  fluid;  the 
bronchial  glands  are  coloured  by  the  black  pigment  brought  to 
them  from  the  lungs;  poisonous  matter,  as  that  of  the  small-pox 
or  venereal,  irritates  and  inflames  the  lymphatics  that  lie  in  the 
course  of  its  introduction  into  the  system.  For  these  reasons  it 
would  appear  to  him,  that  the  arteries  do  not  continue  themselves 
into  the  lymphatics  as  they  do  into  the  veins.  The  observations 
of  M.  Lauth  seem  to  have  proved  the  point,  that  some  of  the 
lymphatics  take  their  origin  from  the  internal  surface  of  the  ar- 
teries ;  and  it  may  be  through  them  that  injections  have  been 
forced  from  one  system  into  the  other. 

The  coats  of  the  lymphatics  generally  are  too  thin  and  trans- 
parent for  an  investigation  of  their  structure ;  but  as  those  of  the 
thoracic  duct  are  sufficiently  large  for  the  purpose,  one  may 
estimate  the  structure  of  other  trunks  by  it.  It  is  thus  ascertained 
that  they  consist  of  two  coats,  an  internal  and  an  external  one. 

The  external  coat  is  somewhat  irregular  in  its  surface,  from 
its  connexion  with  the  adjacent  cellular  substance;  and  has  a 
filamentous  appearance  more  deeply,  which  has  been  considered 
.as  fibrous,  or  muscular,  by  some  anatomists,  owing  to  its  con- 

VOL.  II.— 37 


286  CIRCULATORY  SYSTEM. 

traction  upon  the  application  of  certain  stimulants.  The  inter- 
nal membrane  is  extremely  fine  and  perfectly  transparent,  and 
is  remarkable  for  its  frequent  duplications,  whereby  a  system 
of  valves  is  produced  resembling  those  of  the  veins.  These 
valves  are  generally  of  a  semi-lunar  or  parabolic  shape,  and  are 
arranged  in  pairs,  though,  according  to  Lauth,*  some  of  them  are 
circular,  and  do  not  close  the  canal  entirely.  The  pairs  are  not 
placed  at  stated  distances  from  one  another,  but  vary  in  differ- 
ent parts  of  the  body;  in  some  places  there  are  several  in  the 
course  of  an  inch,  and  in  others  not  one  pair.  As  a  general 
rule,  they  are  less  frequent  as  the  trunk  increases  in  magni- 
tude; hence,  the  thoracic  duct  has  but  very  few  of  them.  The 
yalves,  by  having  their  semi-circumference  fixed,  while  the  dia- 
meter is  loose  and  inclined  in  the  course  of  the  circulation,  pre- 
vent the  retrograde  movement  of  the  contained  fluid.  The  en- 
largement of  the  trunk  at  their  outer  face  into  sinuses,  resem- 
bling those  at  the  valves  of  the  veins,  gives  also  to  the  lympha- 
tic trunk  the  knotted  condition  when  it  is  fullyMnjected. 

The  coats  of  the  lymphatic  vessels,  though  very  thin,  are  yet 
dense  and  extremely  strong,  much  more  in  proportion  than 
those  of  any  other  tubes.  They  are  both  extensible  and  elastic, 
possess  striking  powers  of  spontaneous  contraction  in  the  living 
body,  and  also  in  the  dead,  but  to  a  less  extent.  They  are  fur- 
nished with  arteries  and  veins,  and  probably  with  nerves  also, 
from  their  sensibility  in  a  state  of  inflammation.  And,  as  they 
stand  in  need  of  a  similar  organization  with  other  canals,  their 
parietes  are  said  also  to  have  lymphatics. 

The  absorbent  vessels  are,  by  some,  divided  into  lacteals  and 
lymphatics,!  the  first  term  expressing  those  which  convey  the 
chyle  from  the  intestines,  and  the  second  such  as  are  found  in 
other  parts  of  the  system.  As  the  difference  is  more  in  the 
fluid  conducted  than  in. the  structure  of  the  vessels  themselves, 

*  Loc.  cit. 

j-  This  division  has  been  handed  down  from  the  time  of  Bartholine,  who,  not  sus- 
pecting the  absorbing  powers  of  the  lymphatics,  held  them  only  as  organs  of  circu- 
lation for  restoring  to  the  heart  the  serum  of  the  blood.  The  sagacious  mind  of 
the  late  Dr.  W.  Hunter  first  imagined  their  absorbing  powers,  and  established 
the  theory  of  their  identity  of  function,  in  this  respect,  with  the  lacteals.  The 
priority  of  the  theory  was  warmly  contested  for  Dr.  Monroe,  of  Edinburgh. 


ANATOMY  OP  THE  ABSORBENT  SYSTEM.  287 

the  division  is  rather  superfluous.  There  is  also  a  distinction  of 
the  lymphatics,  arising  from  their  situation,  as  in  the  veins;  some 
of  them  are  called  superficial,  and  the  others  deep-seated.  The 
arrangement  upon  which  this  nomenclature  depends,  is  found 
in  the  head,  trunk,  extremities,  and  in  the  most  of  the  vis- 
cera. The  deep-seated  trunks  are  the  largest,  but  the  least 
numerous. 


Of  the  Lymphatic  Glands. 

The  Lymphatic  or  Absorbent  Glands  or  Ganglions,  some- 
times called  waxen  kernels  in  common  language,  are  an  appen- 
dage of  a  very  important  description  to  the  absorbent  system. 
They  are  flattened  ovoidal  bodies,  of  a  reddish  ash  colour,  in- 
durated so  as  to  afford  a  strong  resistance  to  pressure,  and  of  a 
variable  volume,  from  a  line  to  twelve  lines  in  their  long  dia- 
meter. They  are  found  principally  in  clusters  or  chains,  and 
more  abundant  in  the  neck,  in  the  groin,  in  the  arm-pit,  in  the 
mesentery,  and  about  the  bifurcation  of  the  trachea. 

The  lymphatic  vessels,  in  their  course  towards  the  thoracic 
duct,  have  to  pass  through  one  or  more  of  these  glands.  This 
rule  is  almost  universal;  some  exceptions,  however,  to  it,  in  the 
case  of  the  lower  extremity,  have  been  stated  byJVIr.  Hewson, 
and  in  the  case  of  the  back,  by  Mr.  Cruikshank:*  the  latter  be- 
lieves Mr.  H.  to  have  been  under  a  misapprehension  in  this 
statement  concerning  the  extremities,  as  it  had  not  been  verified 
by  the  result  of  his  own  investigations.  The  vessels  that  enter 
into  the  glands  are  called  vasa  inferentia,  while  those  that  de- 
part from  them  are  the  vasa  efferentia.  As,  owing  to  the  jux- 
taposition of  many  of  these  glands,  the  vessels  between  them 
are  very  short,  this  distinction  would  likewise  seem  almost  su- 
perfluous, because  there  is  scarcely  space  to  apply  the  term  ef- 
ferentia, before  the  same  vessels  enter  the  consecutive  gland, 
thereby  becoming  inferentia.  For  the  most  part,  the  vasa  in- 
ferentia are  more  numerous  and  somewhat  smaller  than  the  ef- 
ferentia. The  former,  as  they  enter  the  gland,  radiate  into 

*  Anat.  of  Absorb,  Vessels,  second  edit.  p.  79.    London,  1790. 


288  CIRCULATORY  SYSTEM. 

smaller  branches,  while  the  latter  are  formed  from  the  junction 
of  smaller  branches. 

Each  lymphatic  gland  is  surrounded  by  a  capsule,  resembling 
condensed  cellular  substance,  which  adheres  very  closely  to  the 
gland,  and  from  which  cause  many  anatomists  are  disposed  to 
deny  its  existence,  at  least  as  a  distinct  membrane.  They  are 
also  abundantly  furnished  with  arteries  and  with  veins  destitute 
of  valves;  but  though  they  are  penetrated  by  nervous  filaments, 
it  is  not  yet  satisfactorily  ascertained  that  any  remain  with  them ; 
it  is,  however,  more  probable  than  otherwise.  Their  connexion 
with  the  surrounding  cellular  substance  is  sufficiently  loose  to 
permit  them,  in  certain  parts,  to  be  slid  moderately  backwards 
and  forwards.  When  this  motion  is  arrested,  it  is  from  inflam- 
mation about  them. 

The  capsule  of  the  lymphatic  gland,  like  that  of  other  glands, 
sends  processes  within  to  keep  its  parts  together,  and  to  con- 
duct the  blood  vessels.  It  also  contains  a  peculiar  fluid  called, 
by  Haller,  succus  proprius,  which  is  principally  found  in  young 
animals,  diminishes  as  they  advance  in  age,  and  finally  disap- 
pears. It  is  of  various  colours,  but  more  frequently  white;  it 
appears  to  have  globular  particles  in  it,  which-  the  late  Mr. 
Hewson,  for  divers  reasons,  thought  to  become  afterwards  the 
red  globules  of  blood. 

When  a  lymphatic  gland  is  injected  with  quicksilver,  it  ap- 
pears to  be  made  up  by  the  minute  branching  of  the  vasa  infe- 
rentia,  and  the  roots  of  the  vasa  efferentia,  the  former  being  con- 
tinued into  the  latter.  There  is  also  some  appearance  of  small 
cells  intermediate  to  these  two  orders  of  vessels.  All  anato- 
mists admit  the  former  opinion;  but  many  reject  the  latter,  un- 
der a  presumption  that  the  appearance  is  delusive.  The  argu- 
ments, however,  seem  to  be  in  favour  of  their  existence.  Mr. 
Cruikshank,*  whose  address  in  these  matters  was  certainly  of 
the  first  order,  declares  that  he  never  failed  to  perceive  them, 
and  particularly  well,  just  as  the  mercury  was  entering  the 
gland.  This  arrangement  is  still  more  readily  made  out  in 
animals,, as  the  horse,  ass,  mule.  It  also  seems,  from  his  ob- 
servations, that  when  there  are  more  than  one  vas  inferens  and 

*  Loc.  cit.  p.  85,  pi.  iii. 


ANATOMY  OF  THE  ABSORBENT  SYSTEM.  289 

eflerens,  there  are  cells  for  each  set,  which  are  kept  distinct 
from  the  cells  of  the  others,  though  they  communicate  freely 
with  their  cognates.  Mr.  Abernethy's  investigations,  on  the 
mesenteric  glands  of  whales,  coincide  with  the  views  of  Mr. 
Cruikshank:  he  states,  indeed,  the  cells  as  being  large  spherical 
bags,  into  which  the  lacteals  plainly  open.  The  celebrated 
Mascagni  also  acknowledges,  and,  indeed,  describes  the  cellu- 
lar structure  of  these  glands,*  which  he  had  ascertained  both  by 
quicksilver  and  by  wax  injections.  The  improved  notions  of 
modern  anatomy,  upon  what  is  called  the  erectile  tissue,  that  is, 
the  cells  intermediate  to  arteries  and  veins,  as  in  the  penis  and 
other  places,  now  considered  rather  as  the  dilated  extremities 
of  vessels,  would  also  assist  in  warranting  the  opinion  advo- 
cated. The  celebrated  Ruysch  thought  that  he  had  discovered 
acini  in  the  lymphatic  glands,  and  sent  his  injected  preparation 
illustrative  of  them  to  Boerhaave.  Some  idea  of  the  enthusiasm 
of  the  old  anatomists  may  be  conceived  by  his  saying,  "  Quan- 
do  jam  clarius  et  perfectius  videbam  haec  omnia,  pra3  gaudio  ex- 
siliebam." 


When  the  absorbing  powers  of  the  lymphatics  had  been 
established  by  Dr.  W.  Hunter,  they  were  for  a  long  time  con- 
sidered as  the  exclusive  functionaries  in  this  operation;  and  the 
opinions  previously  entertained  had  sunk  into  such  disrepute, 
from  some  experiments  of  Mr.  John  Hunter,t  that  they  were 
considered  rather  as  food  for  literary  research  and  curiosity, 
than  for  deliberate  adoption.  In  the  year  1809,  M.  Magendie 
reported  his  experiments  on  absorption,  which  seemed  to  fa- 
vour the  notion  that  the  veins  also  assisted  in  this  office,  a  the- 
ory as  ancient  as  Galen.  The  more  recent  observations  of 
Fohman,  in  1821,  and  Lauth,  in  1824,  on  the  communications 
of  the  lymphatics  with  the  veins,  in  the  midst  of  the  tissues  of 
organs,  and  in  the  lymphatic  glands,  seem  now  to  explain  away 
again  the  theories  of  the  absorbing  powers  of  the  veins,  and  to 

*  Vasor.  Lymph.  Hist. 
f  Med.  Commentaries. 


290  CIRCULATORY  SYSTEM. 

reinstate  the  lymphatics  in  their  reputed  exclusive  functions. 
It  is  also  stated  that  an  anatomist  of  Florence,  M.  Lippi,  has 
still  more  lately  found  several  large  lymphatic  trunks  entering 
into  the  ascending  cava.  The  connexion  of  the  lymphatic  sys- 
tem with  the  vena  cava  ascendens,  and  also  with  the  external 
iliac  veins  has  been  farther  demonstrated  by  certain  preparations, 
exhibited  by  M.  Amussat  to  the  Academic  Royale.*  M.  Fo- 
dera  has,  however,  again  brought  the  subject  under  discussion, 
by  multiplying  the  active  agents  of  this  function,  and  says,  that 
his  experiments  prove  that  all  organized  tissues  enjoy  it,  and 
not  certain  parts  only,  as  has  been  heretofore  supposed;!  from 
which  it  results  that  most  of  the  rules  in  regard  to  the  applica- 
tion of  local  remedies  are  inexact,  and  that  we  should  have 
more  regard  to  the  thickness  and  density  of  tissues,  to  the 
quantity  and  rapidity  of  their  circulation,  than  to  simple  lo- 
cality 4 


CHAPTER  VI. 

OF  THE  SPECIAL  ANATOMY  OF  THE  ABSORBENT  SYSTEM. 
SECT.   I. — OP  THE  ABSORBENTS  OF  THE  HEAD  AND  NECK. 

THE  Superficial  Absorbents  of  the  head  are  found  in  company 
with  the  several  branches  of  the  temporal,  the  occipital,  the 
frontal,  and  the  facial  arteries,  and,  in  order  to  get  into  the 
lymphatic  trunks  leading  to  the  thoracic  duct,  follow  or  rather 
reverse  the  course  of  their  respective  arteries.  There  are  at 
least  two  absorbent  trunks  for  one  arterial,  and  frequently 

*  Am.  Med.  Jour.  vol.  i.  p.  422. 

-}•  Recherches  Experimentales  sur  1' Absorption  et  1'Exhalation.      Paris,  1824. 

*  For  a  most  interesting  and  instructive  series  of  experiments  on  the  laws  and 
phenomena  of  absorption,  see  Philadelphia  Journal  of  the  Medical  and  Physical 
Sciences.     Nos.  6  and  10.    The  experiments  were  executed  by  Drs.  Lawrence, 
Coates,  and  Harlan,  of  this  city. 


ABSORBENTS  OF  THE  HEAD  AND  NECK.          291 

more:  those  on  the  face  are  more  abundant  than  such  as  are  on 
the  side  of  the  cranium,  owing  to  the  excess  of  cellular  substance 
on  the  former.  The  absorbents  of  these  two  regions  anasto- 
mose freely  beneath  the  external  ear,  between  the  skin  and  the 
parotid  gland. 

The  Deep-Seated  Absorbents  of  the  head  have  been  followed 
to  the  membranes  of  the  brain,  but  not  farther.  Ruysch  ob- 
served them  between  the  tunica  arachnoidea  and  pia  mater,  in- 
flated with  air,  and  called  them  vasa  pseudo-lymphatica.  Lan- 
cisius,  Pacchioni,  and  others,  assert  their  having  found  them  in 
the  pia  mater.  Doubts,  however,  are  cast  upon  these  several 
observations,  owing  to  such  vessels  not  having  been  injected 
with  quicksilver,  and  from  the  want  of  a  valvular  appearance 
in  them;  also  from  the  want  of  lymphatic  glands  in  the  brain. 
Their  existence,  however,  would  seem  to  be  sufficiently  proved, 
both  from  general  analogy,  and  from  affections  of  the  brain 
producing  swellings  in  the  glands  of  the  neck.  On  the  dura 
mater  they  have  been  traced  along  the  course  of  its  arteries. 
They  descend  from  the  interior  of  the  cranium  into  the 
neck,  along  the  carotid  and  vertebral  arteries.  The  absence 
of  lymphatic  glands  in  the  cranium  may  be  accounted  for  from 
the  fact,  that  the  ready  tendency  of  these  organs  to  swell  upon 
slight  causes  of  irritation,  would  have  rendered  the  individual 
liable  to  death,  from  compression  of  the  brain,  by  their  tume- 
faction. Mr.  Cruikshank  has  found  lymphatic  glands  in  the 
carotid  canal. 

The  Deep  Lymphatics  of  the'face,  as  those  from  the  interior 
of  the  nose,  of  the  orbit,  of  the  tongue  and  mouth,  attend  the 
arteries  which  respectively  supply  those  parts. 

These  several  absorbents,  from  the  surface  and  from  the  in- 
terior of  the  head,  descend  to  the  base  of  the  cranium,  and  then 
begin  to  pass  through  the  chain  of  lymphatic  glands  situated 
along  the  course  of  the  great  blood  vessels  of  the  neck.  They 
lie,  for  the  most  part,  under  the  ster  no-mas  to  id  muscle,  and, 
when  successfully  injected,  are  thought  to  form  the  most  bril- 
liant plexus  of  absorbents  in  the  whole  frame.  On  each  side 
of  the  neck,  one  or  more  common  trunks  are,  at  length,  formed; 


292  CIRCULATORY  SYSTEM. 

that  on  the  left  side  joins  the  Left  Thoracic  Duct  near  its  ter- 
mination, while  the  one  on  the  right  assists  in  forming  the  duct 
peculiar  to  that  side,  the  Right  Thoracic  Duct,  or,  more  pro- 
perly called,  Brachio  Cephalic. 

The  lymphatic  vessels  of  the  muscles  of  the  neck,  and  those 
of  the  thyroid  gland,  enter  into  the  trunks  of  the  neck.  Ac- 
cording to  Mr.  Cruikshank,  those  of  the  thyroid  gland  may  be 
readily  injected  by  plunging  a  lancet  at  random  into  its  sub- 
stance, and  then  introducing  air  or  quicksilver. 

Of  the  Absorbent  Glands  of  the  Head  and  Neck. 

The  only  claim  of  lymphatic  glands  to  an  existence  in  the 
cavity  of  the  cranium,  is  founded  upon  the  supposition  that  the 
Pineal,  the  Pituitary,  and  Pacchioni's  Glands  are  of  this  cha- 
racter; but  it  is  far  from  being  established,  and  there  seems  in- 
deed to  be  some  dolibt  whether  the  glands  found  in  the  carotid 
canal,  by  Mr.  Cruikshank,  are  not  the  carotid  ganglion  of  the 
Sympathetic,  lately  noticed  by  Laumonier. 

On  the  external  surface  of  the  cranium,  over  the  insertion  of 
the  sterno-mastoid  muscle,  there  are  from  four  to  six  of  a  small 
volume;  on  the  face  there  is  one  or  more  small  ones,  below  the 
zygoma,  and  from  two  to  four  on  the  external  surface  of  the  pa- 
rotid; there  is  one  or  more  small  ones  situated  in  the  substance 
of  the  parotid  gland,  which,  according  to  Burns,  are  generally 
the  seat  of  tumours  falsely  attributed  to  the  parotid  itself.  There 
are  also  some  small  glands  along  the  facial  artery  as  it  ascends 
from  the  base  of  the  jaw  to  the  corner  of  the  mouth. 

On  the  neck  there  are  two  or  more  small  glands,  immediate- 
ly under  the  skin  of  the  symphysis  of  the  jaw,  and  eight  or  nine 
around  the  submaxillary  gland.  The  most  numerous  congeries 
of  glands  on  the  neck  is,  however,  along  its  great  blood  vessels, 
and  covered  more  or  less  by  the  sterno-mastoid  muscle,  being 
principally  between  its  posterior  margin  and  the  anterior  of  the 
trapezius.  Along  the  latter  line  there  are  about  twenty,  in  ad- 
dition to  six  just  above  the  superior  margin  of  the  clavicle.  On 
the  trachea,  just  above  the  sternum,  there  are  four,  forming  the 
upper  end  of  a  series  which  descends  along  the  esophagus  and 
trachea  to  the  root  of  the  lungs. 


ABSORBENTS  OF  THE  UPPER  EXTREMITIES.  293 


SECT.  II. OF  THE  ABSORBENTS  OF  THE  UPPER  EXTREMITIES,  AND  OF 

THE  CONTIGUOUS  PARTS  OF  THE  TRUNK  OF  THE  BODY. 

The  superficial  absorbents  of  the  upper  extremity  are  very  nu- 
merous, and  lie  between  its  skin  and  aponeurosis.  They  begin 
at  the  ends  of  the  fingers  and  thumb;  there  being  two  or  more 
branches  for  each,  both  before  and  behind.  The  posterior 
branches  pass  to  the  back  of  the  hand  and  of  the  fore  arm:  some 
of  them,  more  especially  those  from  about  the  thumb,  run  up 
along  the  radial  side  of  the  fore  arm  to  the  bend  of  the  arm;  but 
by  far  the  greater  part  of  them  incline  very  gradually  in  a  semi- 
spiral  manner  towards  the  ulna,  and  then  to  the  front  of  the  fore 
arm. 

Such  of  the  superficial  vessels  as  come  from  the  front  of  the 
fingers  and  hand,  continue  to  ascend  straight  up  the  fore  arm  to 
its  bend.  These  vessels  of  the  fore  arm  are  so  numerous  that 
for  every  few  lines  there  is  an  ascending  trunk  on  its  circum- 
ference: some  of  them  coalesce,  others  form  plexuses,  and  their 
number  is  much  reduced  at  the  elbow. 

From  the  elbow  the  superficial  lymphatics  ascend  to  the  ax- 
illa in  fifteen  or  twenty  parallel  trunks,  along  the  internal  mar- 
gin and  the  front  surface  of  the  biceps  flexor  cubiti.  The  outer 
side  of  the  arm  has  comparatively  but  few  absorbent  trunks 
upon  it,  but  some  follow  the  course  of  the  cephalic  vein,  pene- 
trate with  it  into  the  axilla,  and  then  join  the  inferior  lympha- 
tics of  the  neck. 

The  Deep  Absorbents  of  the  upper  extremity  attend  the  ar- 
teries, and  are  at  least  two  for  each  principal  artery.  They 
anastomose  with  the  superficial  ones  at  intervals,  and  at  last  ter- 
minate in  the  axillary  glands.  As  they  follow  strictly  the 
course  of  the  arteries,  a  farther  specification  is  needless. 

The  Superficial  Absorbents  of  the  contiguous  portions  of  the 

trunk  of  the  body  are  not  by  any  means  so  numerous  as  those 

of  the  upper  extremity;  they  consequently  are  more  distant 

from  one  another,  and  they  also  go  along  in  a  more  serpentine 

VOL.  II.— 38 


294  CIRCULATORY  SYSTEM. 

manner.  From  the  nape  of  the  neck  to  the  lower  part  of  the 
loins  they  all  converge  to  the  arm-pit.  The  absorbents  which 
are  situated  on  the  front  of  the  pectoralis  major  muscle,  and 
those  on  the  side  of  the  body  from  the  arm-pit  to  the  hip,  also 
converge  to  the  axilla.  In  regard  to  the  two  latter  places,  how- 
ever, some  of  their  absorbents,  by  penetrating  the  parietes  of  the 
thorax  or  abdomen,  respectively  join  the  internal  absorbent 
trunks  of  these  cavities. 

These  several  lymphatics  from  the  upper  extremity  and  from 
the  trunk,  traverse  the  axillary  glands,  and  are  successively  re- 
duced in  number  to  four  or  five  voluminous  trunks,  which  sur- 
round the  subclavian  artery.  While  in  the  axilla  they  are  re- 
enforced  by  the  deep  lymphatics  from  beneath  the  pectoralis 
major,  the  latissimus  dorsi,  and  the  shoulder.  Their  number 
being  again  reduced,  they  go  along  the  subclavian  vein  over  the 
first  rib;  those  of  the  left  side  open  either  into  the  thoracic  duct 
at  its  termination,  or  into  the  subclavian  vein  near  it;  but  those 
on  the  right  are  finally  assembled  into  the  single  large  trunk, 
brachio-cephalic,  which  discharges  into  the  angle  of  junction  of 
the  right  internal  jugular  and  subclavian  vein. 


Msorbent  Glands  of  the  Upper  Extremity. 

These  glands  are  rarely  found  on  the  fore  arm,  but  when  they 
do  exist,  it  is  in  the  course  of  the  deep  absorbents,  and  they  are 
very  small,  and  but  few.  From  one  to  four  are  found  scattered 
on  the  front  of  the  elbow  and  internal  condyle.  From  four 
to  seven  exist  along  the  sheath  of  the  humeral  vessels  and 
nerves. 

The  axillary  glands  are  very  numerous,  and  of  different  sizes; 
they  are  dispersed  throughout  the  cellular  substance  of  the  ax- 
illa, reposing  on  the  serratus  major  anticus,  between  the  pecto- 
ral muscles  and  those  of  the  shoulder,  and  being,  for  the  most 
part,  below  the  axillary  vessels  and  nerves,  but  some  reposing 
immediately  upon  them,  and  forming  a  chain  from  the  lower 
part  of  the  axilla  to  the  clavicle.  Their  number  is  from  fifteen 
to  thirty-five  or  forty.  All  the  absorbents  which  observe  the 


ABSORBENTS  OF  THE  UPPER  EXTREMITIES.  295 

route  of  the  axilla  to  reach  the  thoracic  duct  have  to  pass  through 
these  glands. 


SECT.  III. —ABSORBENTS  OF  THE  INFERIOR  EXTREMITIES,  AND  OF  THE 
CONTIGUOUS  PARTS  OF  THE  TRUNK  OF  THE  BODY. 

The  superficial  absorbents,  like  those  of  the  upper  extremity, 
are  placed  between  the  skin  and  the  aponeurosis,  in  the  cellular 
tissue  that  contains  the  subcutaneous  veins.  They  are  also  very 
abundant,  and  are  found  every  few  lines  on  the  circumference 
of  the  limb;  they  are,  however,  more  numerous  internally  than 
externally,  and,  for  the  most  part,  run  upwards. 

Those  on  the  inner  or  anterior  side  of  the  limb,  are  first  per- 
ceived on  the  back  of  the  toes  and  foot.  They  incline  over  the 
front  of  the  ankle,  and  its  internal  face  to  the  inner  side  of  the 
leg;  they  then  ascend  over  the  inner  side  of  the  knee,  and  along 
the  same  side  of  the  thigh  to  the  groin.  The  superficial  absor- 
bents of  the  back  of  the  lower  extremity  are  first  perceived  on 
the  sole  of  the  foot.  They  ascend  along  the  back  of  the  outer 
ankle  and  of  the  leg  above  the  knee;  they  then  incline  semi- 
spirally  inwards,  so  as  to  bring  themselves  to  the  front  of  the 
thigh.  These  several  absorbents,  though  there  are  but  few  on 
the  foot,  augment  continually  in  number  by  new  accessions  in 
their  ascent.  All  those  on  the  posterior  internal  face  of  the 
thigh  wind  over  its  internal  side,  while  such  as  are  on  its  pos* 
terior  external  face  wind  over  the  outer  side,  to  reach  the  ingui- 
nal glands. 

The  Deep  Absorbents  adhere  to  the  arteries,  being  at  least 
two  to  each,  and  adopting  the  same  distribution  and  nomencla- 
ture. The  anterior  tibial  begins  in  the  sole  of  the  foot,  and 
arises  to  its  back  between  the  two  first  metatarsal  bones;  ano- 
ther branch  begins  on  the  dorsum  of  the  foot.  The  first  pur- 
sues the  course  of  the  anterior  tibial  artery  through  the  inter- 
osseal  ligament  to  the  ham,  the  second  frequently  join  the 
peroneal  absorbents  about  half  way  up  the  leg.  The  posterior 
tibial  and  the  peroneal  absorbents,  as  they  cruise  along  their 
respective  arteries,  do  not  require  any  farther  comment.  There 


296  CIRCULATORY  SYSTEM. 

is  a  fourth  set  of  these  deep  absorbents,  amounting  to  two  Of 
three  in  number,  which  attend  the  external  saphena  vein,  and 
come  from  the  external  side  of  the  foot.  Getting  between 
the  heads  of  the  gastrocnemii  muscles,  th'ey  are  re-enforced  by 
other  trunks  , from  this  muscle;  some  of  the  branches  then  asso- 
ciate themselves  with  the  superficial  lymphatics,  and  others  pe- 
netrate the  ham  so  as  to  join  the  deep  trunks  there. 

The  deep  absorbents  of  the  leg  coalesce  partially  in  the  ham 
and  ascend  along  the  popliteal  artery.  On  the  thigh,  there  are 
from  four  to  eight  of  these  trunks  attending  the  femoral  artery, 
and  receiving  additions  as  the  latter  detaches  branches. 

There  are  two  or  three  lymphatic  vessels  on  each  side  of  the 
penis,  which  begin  at  its  glans  and  prepuce,  and  traversing  the 
length  of  this  organ,  wind  above  the  external  abdominal  ring  to 
join  the  nearest  inguinal  gland.  There  are  several  from  the 
side  of  the  scrotum  and  perineum,  which  ascend  along  the  chord 
and  thigh  to  join  also  the  nearest  inguinal  gland.  In  the  fe- 
male, those  of  the  labia  externa  and  clitoris  correspond  with 
those  of  the  scrotum  and  penis. 

The  superficial  absorbent  trunks,  from  the  lower  front  of  the 
abdomen,  are  not  numerous:  they  descend  and  converge  also  to 
the  inguinal  glands.  Some  of  those  from  the  loins,  such  as  do 
hot  ascend  to  the  axilla,  advance  to  the  inguinal  glands.  Those 
of  the  buttocks  do  the  same. 


Msorbent  Glands  of  the  Lower  Extremities. 

Absorbent  Glands,  below  the  knee,  are  not  abundant,  or,  in- 
'deed,  very  common;  yet  one  or  two  exist  sometimes  in  the 
course  of  the  anterior  tibial  artery  in  the.  upper  part  of  the 
leg.  The  popliteal  glands  are  three  or  four;  they  are  small 
and  scattered  at  wide  intervals  in  the  fat  of  the  ham  around  its 
Vessels.  From  the  latter  to  the  groin,  they  are  not  usually 
found  at  all. 

The  Inguinal  Glands  are  amongst  the  largest  in  the  system; 
they  repose  along  the  anterior  margin  of  Poupart's  ligament  and 
'a  little  below,  and  are  readily  felt  beneath  the  skin.  The  su- 


DEEP  ABSORBENTS  OF  THE  PELVIS.  297 

perficial  vary  in  number,  in  different  individuals,  From  seven  to 
twenty,  being  more  numerous  as  they  are  smaller,  and  are 
placed  between  the  laminae  of  the  fascia  superficialis.  They 
receive,  first  of  all,  the  superficial  lymphatics  of  all  the  parts 
mentioned.  The  deep-seated  are  smaller,  are  a  little  lower 
down  on  the  thigh,  and  lie  along  the  course  of  the  femoral  arte- 
ry, beneath  the  aponeurosis  of  the  thigh;  they  are  from  three 
to  seven  in  number,  but  are  much  less  constant  than  the  super- 
ficial. 


SECT.  IV. DEEP  ABSORBENTS  OF  THE  PELVIS. 

The  Deep  Absorbents  of  the  parietes  of  the  pelvis,  as  in  other 
cases,  attend  the  arteries  of  the  part  and  have  the  same  names. 
The  obturators  come  from  the  heads  of  the  adductor  muscles, 
and,  passing  through  the  obturator  foramen,  end  in  the  hypo- 
gastric  glands.  The  ischiatics  come  from  the  small  muscles  on 
the  back  of  the  hip  joint,  and  getting  into  the  pelvis  along  with 
the  sciatic  artery,  they  also  terminate  in  the  hypogastric  glands. 
The  gluteals  come  from  the  three  gluteal  muscles,  and  entering 
the  pelvis  along  with  the  artery  at  the  superior  margin  of  the 
sciatic  notch,  they  likewise  terminate  in  the  hypogastric  glands 
along  with  some  vessels  from  the  anus  and  the  perineum.  The 
ilio-lumbar,  the  sacral,  and  the  circumflex  iliac  absorbents,  also 
follow  their  respective  arteries  and  terminate  in  the  nearest 
glands. 

The  absorbents  of  the  Testicle  are  numerous  and  large:  ao 
cording  to  Dr.  W.  Hunter,*  they  can  sometimes  be  very  com- 
pletely injected  by  a  pipe  thrust  into  the  substance  of  the  testi* 
cle,  and,  according  to  Cruikshank,  very  advantageously  from 
the  vas  deferens.-)-  They  form  two  layers,  one  superficial  coming 
from  the  txmiea  vaginalis  testis,  and  the  other  from  the  substance 
of  the  gland.  They,  finally,  unite  into  some  six  or  eight  trunks, 
whichj  ascend  with  the  chord  through  the  abdominal  canal.  Oc- 
casionally, one  or  more  of  them  is  as  large  as  a  crow-quill.  By 
following  the  course  of  the  spermatic  artery,  they  at  last  termi- 
nate in  the  lumbar  glands. 

*  Loc,  cit.  f  Loc,  cit,  p,  155,  t  Mascagni,  loc.  cit, 


293  CIRCULATORY  SYSTEM. 

The  deep  absorbents  of  the  Penis  accompany  the  arteries, 
and,  therefore,  either  get  into  the  pelvis  beneath  the  symphysis 
of  the  pubes,  or  along  the  crura  and  the  tuberosities  of  the  is- 
chia;  hence,  a  chancre  on  the  prepuce  causes  bubo,  while  one 
on  the  glans  very  rarely  does,  and  yet  the  constitution  will  be 
equally  affected.*  These  absorbents  terminate  in  the  hypogas- 
tric  glands. 

The  deep  absorbents  of  the  Clitoris  follow,  in  the  same  way, 
the  internal  pudic  artery. 

The  absorbents  of  the  Urinary  Bladder  are  also  numerous, 
and  pass  in  several  trunks  from  its  sides  to  the  hypogastric 
glands.  Those  of  the  prostate  gland  and  vesiculse  seminales 
are  associated  with  them. 

The  absorbents  of  the  lower  part  of  the  vagina  accompany 
the  round  ligament  of  the  uterus  through  the  abdominal  canal, 
and,  finally,  anastomose  with  those  of  the  uterus.  Those  of  the 
upper  portion  of  the  vagina  are  immediately  associated  with 
such  as  belong  tq  the  uterus. 

The  absorbents  of  the  uterus  are  not  so  well  seen  in  the  un- 
impregnated  state,  but  in  impregnation  they  are  so  prodigious- 
ly numerous,  that  when  injected  with  quicksilver,  one  is  al- 
most tempted  to  suppose  that  the  uterus  consists  entirely  of 
them.  Mascagni's  plate  on  this  subject  is  an  exquisite  speci- 
men.! As  they  all  terminate  in  the  hypogastric  trunks,  the 
latter  are  in  such  case  as  large  as  goose-quills.J 

The  hypogastric  plexus,  from  these  several  accessions  from 
the  parietes  and  viscera  of  the  pelvis,  becomes  very  numerous, 
and  follows  the  course  of  the  hypogastric  artery  in  ascending 
into  the  loins. 

There  are  likewise  some  spermatic  absorbents  in  the  female, 
•called  so  from  attending  the  vessels  of  the  same  name.  They 
come  from  theovarium,  the  Fallopian  tube,  and  the  round  liga- 
ment, to  terminate  in  the  lumbar  glands;  they  anastomose  be- 
low with  those  of  the  uterus. 

*  Cruikshank,  loc.  cit.          f  Loc,  cit.          *  Cruikshank,  loc.  cit. 


ABSORBENTS  OF  THE  ORGANS  OF  DIGESTION.  299 


Of  the  Glands  of  the  Pelvis. 

Some  few  glands  lie  beneath  the  glutens  maximus  muscle, 
but  the  majority  are  within  the  pelvis.  Those  which  are  called 
the  External  Iliac  are  at  least  six,  frequently  more,  and  extend 
from  Poupart's  Ligament  to  the  lower  part  of  the  loins,  being 
planted  along  the  external  iliac  artery,  both  above  and  belov.'. 
The  Hypogastric  or  Internal  Iliac  Glands  are  rather  more  nu- 
merous than  the  others,  and  form  a  chain  along  the  hypogastric 
artery.  The  latter  are  much  disposed  to  form  large  indurated 
masses  from  diseases  of  the  rectum,  uterus,  and  bladder.* 


SECT.  V. — ABSORBENTS  OF  THE  ORGANS  OF  DIGESTION. 

The  Absorbents  of  the  Stomach  are  very  numerous,  and  lie  in 
two  planes;  one  is  superficial,  being  immediately  beneath  the 
peritoneal  coat,  and  the  other  is  profound,  being  placed  be- 
tween the  muscular  and  the  mucous  coat.  They  are,  finally, 
assembled  into  three  divisions,  which  follow  the  course  of  the 
principal  blood  vessels  of  this  organ. 

One  division,  coming  from  the  anterior  and  the  posterior 
faces  of  the  stomach,  converges  to  its  lesser  curvature,  and 
passes  through  some  six  or  eight  small  glands  in  the  adjacent 
portion  of  the  lesser  omentum.  Inclining  to  the  right  of  the 
cardiac  orifice,  they  then  pass  through  some  glands  common  to 
them  and  to  the  deep  lymphatics  of  the  liver.  Their  numbers 
being  reduced,  they  then  descend  behind  the  pancreas,  and  ter- 
minate in  the  thoracic  duct  near  the  creliac  artery. 

The  second  division  comes  from  the  left  inferior  portion  of 
the  stomach,  and  from  its  greater  extremity,  and,  blending  with 
the  absorbents  of  the  spleen  and  pancreas,  goes  with  them  inta 
the  thoracic  duct. 

The  third  division  comes  from  the  right  inferior  portion  of 
the  stomach,  and,  assembling  towards  the  pylorus,  are  subse- 

*  Cruikshank,  loc.  cit. 


300  CIRCULATORY  SYSTEM. 

quently  mixed  with  some  of  the  absorbents  of  the  liver  and  of 
the  small  intestines,  and  go  along  with  them  into  the  thoracic 
duct. 

The  Absorbents  of  the  Great  Omentum  join  those  of  the 
stomach  and  of  the  colon,  at  the  points  most  convenient  to 
them. 

.  The  Absorbents  of  the  Small  Intestines,  like  those  of  the 
stomach,  are  both  superficial  and  deep,  and  from  the  function  of 
conveying  chyle,  have  been  called  lacteals,  or  chyliferous  ves- 
sels. As  the  chyle,  however,  can  only  be  absorbed  by  the  deep 
ones;  and,  as  they  and  th§  superficial  have  common  trunks,  as 
they  also  absorb,  from  the  intestines,  fluids  not  converted  into 
chyle,  there  seems  to  be  no  necessity  for  distinguishing  them 
by  a  particular  epithet.  The  deep  are  in  the  cellular  coat  of  the 
intestine,  and  follow  the  ramifications  of  the  arteries,  being  dou- 
ble their  number.  The  superficial,  being  immediately  beneath 
the  peritoneal  coat,  run  for  some  distance,  longitudinally,  on  the 
gut,  and  then  turn  off  to  the  mesentery  at  right  angles. 

On  the  mesentery  these  absorbents  are  not  rigidly  bound  to 
the  course  of  the  blood  vessels;  they  converge  in  a  slightly  tor- 
tuous manner  from  its  circumference  to  its  root.  They  anasto- 
mose with  one  another,  by  which  their  number  is  reduced; 
and  they  also  have  to  pass  through  the  series  of  mesenteric 
glands.  The  lacteals  of  the  duodenum  and  jejunum  are  larger 
and  more  numerous  than  those  of  the  ileum,  in  the  proportion 
of  the  greater  extent  of  the  internal  surface  of  the  former  intes- 
tines, from  the  number  of  their  valvulae  conniventes.  The  ves- 
sels of  the  mesentery,  after  having  cleared  the  series  of  glands, 
and  held  some  intercourse  with  the  lymphatics  of  the  spleen, 
liver,  stomach,  and  pancreas,  are  reduced  at  last  into  one  or  more 
large  trunks,  which,  observing  the  course  of  the  superior  me- 
senteric artery,  empty  near  the  root  of  the  latter,  but  some- 
times lower  down,  into  the  thoracic  duct. 

The  absorbents  of  the  Large  Intestines  are  much  less  nume- 
rous than  those  of  the  small.  They  are  also  superficial  and  deep, 


ABSORBENTS  OF  THE  ORGANS  OF  DIGESTION.  301 

and  observe  the  course  of  the  felood  vessels.  Those  from  the 
right  portion  and  middle  of  the  colon  join  the  lacteals  of  the  me- 
sentery, while  such  as  belong  to  the  sigmoid  flexure  follow  the 
inferior  mesenteric  artery  up  to  the  lumbar  glands.  Those  of 
the  rectum  go  partly  into  the  lumbar  and  partly  into  the  hypo- 
gastric  glands,  and  as  its  blood  vessels  are  more  numerous  than 
those  of  other  portions  of  the  large  intestines,  its  absorbents  are 
in  the  same  proportion.* 

The  Absorbents  of  the  Liver  are  exceedingly  numerous,  and 
are  also  injected  with  unusual  ease  from  the  larger  into  the 
smaller  trunks,  from  the  imperfection  of  the  valvular  arrange- 
ments. They  are  also  superficial  and  deep. 

The  Superficial  Absorbents  of  the  upper  surface  of  the  liver 
run  in  several  divisions,  the  number  of  which  is  unsettled.  Those 
near  the  middle  front  of  the  liver  assemble  into  six  or  more  trunks, 
which  ascend  the  suspensory  ligament,  and  enter  the  thorax  be- 
tween the  diaphragm  and  the  sternum.  They  are  joined  by  se- 
veral trunks  from  the  diaphragm,  and,  continuing  to  ascend  up 
the  anterior  mediastinum  between  its  laminae  behind  the  sternum, 
they  are  re-enforced  by  contributions  from  the  pericardium,  from 
the  thymus  gland,  and  from  the  anterior  parietes  of  the  thorax. 
The  division  then  crosses  the  upper  end  of  the  descending  cava, 
and  those  from  the  two  sides  assembling,  they  go  in  one  or  more 
large  trunks  along  the  left  vena  innominata,  and  finally  empty 
into  the  left  thoracic  duct  near  its  termination.  Sometimes  they 
enter  into  the  right  thoracic  duct.  It  occasionally  happens  that 
a  detachment  of  this  division,  instead  of  ascending  through  the 
mediastinum,  is  directed  towards  the  coronary  ligament  of  the 
liver;  and  being  there  joined  by  other  vessels,  it  enters  imme- 
diately into  the  thoracic  duct  at  the  upper  part  of  the  abdominal 
cavity,  or  at  the  lower  part  of  the  thorax. 

Another  division  comes  from  the  upper  surface  of  the  right 
lobe,  and  gaining  the  right  lateral  ligament,  penetrates  into  the 
thorax  through  the  diaphragm,  and  advancing  along  the  costal 


*  Cruik shank,  loc.  cit. 
VOL.  II.— 39 


302  CIRCULATORY  SYSTEM. 

margin  of  this  muscle,  terminates  in  the  first  division  under  the 
sternum.  Sometimes  one  of  its  branches,  thrice  as  large  as  a 
crow-quill,  runs  backward  to  the  spine,  and  is  inserted  into  the 
thoracic  duct  behind  the  oesophagus,  without  passing  through 
any  gland;  there  are  also,  occasionally,  several  other  arrange- 
ments of  the  trunks  of  this  division.* 

Another  division  comes  from  the  upper  surface  of  the  left  lobe 
of  the  liver,  and  its  trunks,  advancing  to  the  left  lateral  ligament, 
get  into  the  thorax  through  the  diaphragm.  Some  of  the  trunks 
then  run  forward  on  the  convexity  of  this  muscle,  to  terminate 
in  the  trunks  Under  the  sternum,  while  others  retire  backward 
to  end  in  the  glands  around  the  oesophagus,  immediately  above 
the  diaphragm. 

There  are  various  departures  from  this  general  arrangement 
of  the  absorbents  on  the  upper  surface  of  the  liver;  as  their 
trunks  invariably  reach  the  thoracic  duct,  ultimately,  the  par- 
ticular routes  do  not  seem  to  be  rigidly  fixed. 

The  Superficial  Absorbents  of  the  under  surface  of  the  liver 
present,  also,  diversities,  but  they  are  seldom  arranged  into  so 
many  divisions  as  those  of  the  upper  surface.  They  communicate 
freely  with  the  latter,  and  also  with  the  profound,  and,  finally, 
assembling  in  the  transverse  fissure,  they  descend  along  the  cap- 
sule of  Glisson  to  join  and  anastomose  with  the  contiguous 
trunks  from  the  alimentary  canal,  from  the  pancreas,  and  the 
spleen. 

The  Deep  Absorbents  of  the  liver  follow  the  branching  of  the 
vena  portarum,  and,  emerging  at  the  transverse  fissure,  pass 
through  the  glands  in  the  capsule  of  Glisson,  associating  them- 
selves at  the  same  time  with  the  superficial  trunks,  and  having  a 
common  termination  with  them.  By  putting  a  ligature  around 
the  vena  portarum  of  a  living  animal,  many  of  them  are  in- 
cluded in  it ;  they  then  become  exceedingly  turgid,  and  are  seen 
to  diverge  through  the  liver  like  the  pori  biliarii. 

The  liver  is  said  to  be  more  abundantly  furnished  with  ab- 
sorbents than  any  other  vise  us. 

*  Cruikshank,  loc.  cit. 


ABSORBENTS  OF  THE  ORGANS  OF  DIGESTION.  ^  303 

The  Absorbents  of  the  spleen  are  also  superficial  and  deep- 
seated.  The  former  are  between  the  peritoneal  and  the  proper 
coat,  and  are  injected  with  some  difficulty  in  the  human  subject, 
but  are  very  demonstrable  and  numerous  in  the  calf.  The  latter 
emerge  at  the  fissure  of  the  spleen,  and,  traversing  the  glands 
tha/  lie  along  the  course  of  the  splenic  artery,  receive  successively 
the  absorbents  from  the  pancreas.  They,, finally,  end  in  the  tho- 
racic duct,  after  reciprocal  junctions,  and  anastomose  with  the 
vessels  from  the  stomach  and  liver. 

The  Absorbents  of  the  Pancreas  are  also  numerous,  and  may 
be  injected,  contrary  to  their  circulation,  from  those  of  the  liver. 
They  arise  from  the  substance  of  the  pancreas,  like  its  vessels, 
by  short  trunks,  which  join  those  of  the  Splenic  Plexus  at  right 
angles. 

The  Absorbents  of  the  Kidneys  are  superficial  and  deep ;  the 
former,  though  numerous,  are  too  small  in  the  healthy  state  of 
these  organs  to  be  well  seen,  but  they  become  very  distinct  from 
disease,  and  converge  from  its  periphery  to  its  fissure.  The  deep 
absorbents  accompany  the  vessels,  and,  emerging  with  them  at 
the  fissure,  are  joined  with  the  superficial;  they  all  then  run 
along  the  emulgent  vessels,  and  have  frequent  anastomoses  with 
those  of  the  testicles  or  ovaries,  and  with  those  of  the  capsulae 
renales.  These  absorbents  may  be  filled  by  putting  a  pipe  into 
the  excretory  duct  of  the  kidney. 

The  absorbents  of  the  Capsulae  Renales  unite  to  those  from 
the  kidneys,  and,  therefore,  terminate  with  them  in  the  lumbar 
glands. 

Of  the  Absorbent  Glands  of  the  Abdomen. 

The  cavity  of  the  abdomen  contains  many  more  glands  than 
any  other  region  of  the  body,  on  account  of  the  very  great  ex- 
tension of  the  serous  system  in  it,  of  the  functions  exercised  by 
its  viscera,  and  of  its  being  traversed  by  the  absorbents  of  the 
lower  extremities.  Many  of  these  bodies  have  already  been  de- 
scribed under  the  denomination  of  hypogastric,  and  external 


304  CIRCULATORY  SYSTEM. 

iliac ;  in  addition  to  which  there  are  a  few  between  the  laminae 
of  the  mesorectum  in  front  of  the  sacrum. 

The  Mesenteric  Glands  are  exceedingly  numerous,  and  amount 
to  between  one  and  two  hundred ;  they  begin  at  an  inch  or  two 
from  the  small  intestines,  and  may  be  traced  to  the  root  of  the 
mesentery,  being  placed  between  its  layers,  on  the  convex  side 
of  the  upper  mesenteric  artery.  As  the  intestinal  canal  is  longer 
in  some  individuals  than  in  others,  they  are  proportionately  more 
numerous.  Their  largest  size  seldom  exceeds  that  of  an  almond : 
those  belonging  to  the  jejunum  are  rather  more  developed  than 
such  as  belong  to  the  ilium,  and  they  all  augment  in  size  as  they 
approach  the  root  of  the  mesentery. 

The  Glands  of  the  Mesocolon  are  placed  between  the  laminae 
of  this  membrane,  near  the  intestine ;  they  receive  the  absorbents 
from  the  large  intestines,  are  much  smaller  than  those  of  the  me- 
sentery, and  their  number  seldom  exceeds  fifty.  Some  few  of 
them  are  situated  near  the  root  of  the  mesocolon.  They  are  by 
no  mea'ns  so  disposed  to  tumefaction  from  scrofulous  affections 
as  those  of  the  Mesentery.  It  is  stated  by  Winslow,  that  he  de- 
monstrated to  the  Academy  of  Sciences  at  Paris,  chyle  in  the 
absorbents  of  the  Mesocolon ;  this  fact  will  assist  us  in  account- 
ing for  the  effects  of  nutritive  glysters. 

The  Gastro-Epiploic  Glands  are  situated  between  the  lami- 
nae of  the  omenta,  where  they  join  the  curvatures  of  the  stomach. 
Their  number  seldom  exceeds  four  or  five  for  each  curvature, 
and  they  receive  the  lympathics  of  the  stomach  and  omenta. 

The  Caeliac  Glands  are  those  which  belong  to  the  liver,  the 
spleen,  and  the  pancreas ;  they  follow  the  course  of  the  blood 
vessels  of  these  organs,  and  are  traversed  by  their  absorbents. 
The  trunk  of  the  vena  portarum  is  surrounded  by  them,  and  Mr. 
Cruik shank  says,  that  he  has  seen  the  biliary  and  pancreatic 
ducts  in  a  state  of  compression  from  their  tumefaction. 

The  Lumbar  Glands  are  very  numerous  and  large;  they  are 
scattered  over  the  whole  region  from  the  base  of  the  sacrum  to 


ABSORBENTS  OF  THE   VISCERA   OF    THE   THORAX.  305 

the  pillars  of  the  diaphragm,  lying  on  each  side  of  the  bodies  of 
the  lumbar  vertebrae,  and  in  front  of  the  abdominal  aorta  and 
vena  cava,  being  concealed  by  the  root  of  the  mesentery  and  of 
the  mesocolon.  They  may  be  considered  as  continuations  of 
all  the  preceding  congeries  of  glands  in  the  abdomen,  and,  there- 
fore, when  they,  along  with  the  vessels  leading  to  them,  are  suc- 
cessfully injected,  they  form  so  thick  a  plexus  of  absorbents, 
reaching  from  the  pelvis  to  the  concavity  of  the  diaphragm,  that 
the  great  blood  vessels  can  scarcely  be  seen  for  them.  Many 
of  the  vessels  reaching  from  one  to  another,  are  as  large  as  a 
crow-quill. 


SECT.  VI. ABSORBENTS  OF  THE  VISCERA  OF  THE  THORAX. 

The  Absorbents  of  the  Lungs  are  thought  to  be  next  in  abun- 
dance after  those  of  the  liver,  and  are  likewise  divided  into  two 
sets,  the  superficial  and  the  deep-seated.  The  former  are  be- 
neath the  pleura  pulmonalis.  Mr.  Cruikshank*  says,  that  they 
are  not  always  to  be  found,  though  commonly  he  has  readily 
shown  them  covering  with  their  meshes  the  whole  external  sur- 
face of  the  lung.  The  larger  meshes  follow  the  interstices  of 
the  lobules,  and  within  them  are  others  of  extreme  delicacy. 
The  same  author  states,  that  one  of  the  easiest  methods  of  find- 
ing them,  is  to  inflate  the  lungs  of  a  still-born  child,  from  the 
trachea,  and  the  air  passing  from  its  proper  cells,  will  get  into 
the  absorbents;  a  puncture  being  then  made  into  one  of  the  lat- 
ter, quicksilver  may  be  very  readily  introduced.  Some  of  their 
trunks  penetrate  to  the  bottom  of  the  fissures  of  the  lungs,  and 
pass  through  the  glands  there,  while  others  continue  more  super- 
ficial along  the  internal  face  of  the  lung,  and  so  reach  the  bron- 
chial glands. 

The  deep  absorbents  of  the  lungs  observe  the  course  of  the 
pulmonary  vessels  and  of  the  bronchise.  They  arise  from  the 
substance  of  the  lung,  anastomose  very  freely  with  the  superfi- 
cial vessels,  and,  in  parting  from  the  lung,  pass  through  the 
bronchial  glands,  where  they  are  joined  by  the  superficial. 

By  the  junction  of  the  branches  from  the  left  lung,  three  con-  ' 

*  Loc.  cit.  p.  194. 


306  CIRCULATORY  SYSTEM. 

siderable  trunks  are  formed;  one,  which  is  sometimes  the  size 
of  a  goose-quill,  is  inserted  into  the  thoracic  duct,  immediately 
behind  the  bifurcation  of  the  trachea ;  another  ascends  between 
the  trachea  and  the  oesophagus,  to  join  the  thoracic  duct  near 
its  termination,  and  the  third  joins  the  glands  belonging  to  the 
absorbents  of  the  heart.* 

The  absorbents  of  the  right  lung  also  coalesce  into  three  prin- 
cipal trunks  at  the  root  of  the  lung :  one  of  them  ascends  across 
the  front  of  the  superior  cava,  making,  in  its  course,  many  ele- 
gant convolutions,  and  at  length  terminates  in  the  second  trunk 
on  the  left  side.t  The  other  trunks,  ascending  on  the  side  of 
the  trachea,  and  having  traversed  their  glands,  discharge  into 
the  right  thoracic  or  brachio-cephalic  trunk,  or  else  near  it  into 
the  right  internal  jugular,  or  into  the  right  subclavian  vein. 
There  are,  in  these  respects,  diversities  in  different  subjects. 

The  trunks  of  the  Absorbents  of  the  Heart  follow  the  course 
of  the  coronary  vessels,  and  distribute  themselves  by  branches 
over  its  whole  surface.  They  are,  without  previous  manage- 
ment, easily  discovered;  but  if  the  heart  be  macerated  in  water 
for  several  days,  so  as  to  become  somewhat  putrid,  the  absor- 
bents are  filled  and  distended  by  the  gazeous  exhalation:  on  the 
puncture  of  one  of  these  vessels  and  the  introduction  of  a  pipe, 
they  may  all  be  readily  filled. 

There  are  three  principal  trunks  of  these  absorbents;  one  fol- 
lows the  right  coronary  artery  to  the  root  of  the  aorta,  and  then 
ascends  over  the  front  surface  of  the  latter  to  the  top  of  its  arch, 
where  it  enters  a  gland.  The  other  two  trunks  follow  the  two 
principal  branches  of  the  left  coronary  artery,  and,  coalescing 
near  its  origin,  they  ascend  to  the  bifurcation  of  the  pulmonary 
artery,  and  from  that  along  the  posterior  face  of  the  arch  of  the 
aorta,  to  enter  a  gland  between  it  and  the  trachea.  These  se- 
veral vessels  subsequently  traverse  the  lymphatic  glands  about 
the  trachea,  common  to  the  heart  and  to  the  lungs;  and  ulti- 
mately terminate  under  varied  circumstances,  either  directly  or 
indirectly,  in  the  left  thoracic  duct,  the  left  internal  jugular,  or 
the  subclavian  vein.  Mr.  Cruikshank  says,  that  the  right  coro- 

*  Cruikshank,  loc.  cit.  f  Cruikshank,  loc.  cit. 


ABSORBENTS  OF  THE  PARIETES  OF  THE  TRUNK.  307 

nary  trunk  empties  into  the  lymphatic  trunks  of  the  right  side 
of  the  neck,  which  shows  that  there  is  no  fixed  arrangement. 

The  Absorbents  of  the  Pericardium  may  also  be  found;  they 
terminate,  like  the  others  of  the  heart,  in  the  bronchial  glands, 
and  are  particularly  associated  with  those  of  the  thymus  gland. 

The  Absorbents  of  the  CEsophagus  are  so  numerous  as  to 
form  a  plexus  from  one  end  to  the  other  of  it.  They  run  into 
the  bronchial  glands,  and,  therefore,  have  a  common  termina- 
tion with  the  absorbents  of  the  heart  and  lungs.  Mr.  Cruikshank 
says,  that  he  has  reason  to  believe  that  he  has  seen  life  sustained 
through  them  alone  and  the  absorbents  of  the  mouth,  in  a  case 
where  stricture  prevailed  for  some  months  just  above  the  cardia, 
and  where  the  food,  after  remaining  for  three  or  five  minutes 
in  the  oesophagus,  was  vomited  up.* 

The  Absorbents  of  the  Thymus  Gland  are  very  abundant  in 
the  infant,  but  diminish  with  the  rest  of  the  structure  in  the 
adult:  they  terminate  in  the  bronchial  glands  also. 


SECT.  VII. THE  ABSORBENTS  OF  THE  PARIETES  OF  THE  TRUNK. 

t 

In  addition  to  the  absorbents  mentioned  as  belonging  to  the 
internal  and  external  parietes  of  the  pelvis,  there  are  some 
others  belonging  to  this  cavity,  as  the  ilio  lumbar,  the  sacral, 
and  the  circumflex. 

The  Ilio  Lumbar  Lymphatics  come  from  the  parts  to  which 
the  artery  of  the  same  name  is  distributed,  and,  assembling  into 
two  or  more  large  trunks  which  pass  beneath  the  psoas  magnus 
muscle,  one  of  them  joins  the  lumbar  glands,  and  another  the 
hypogastric. 

The  Sacral  Lymphatics  arise  from  the  cellular  tissue  in  front 
of  the  sacrum  and  from  the  spinal  canal  in  the  latter.  Emerging 

*  A  case  somewhat  similar  has  occurred  in  the  practice  of  Dr.  Physick. 


308  CIRCULATORY  SYSTEM. 

through  its  foramina  in  front,  they  terminate  in  the  lower  part 
of  the  lumbar  and  in  the  hypogastric  plexus. 

The  Circumflex  Iliac  Lymphatics  attending  the  artery  of  the 
same  name,  arise  from  the  lateral  inferior  parietes  of  the  abdo- 
men>  in  the  thickness  of  its  broad  muscles,  the  several  branches 
assemble  into  a  few  trunks,  which  descend  along  the  posterior 
margin  of  Poupart's  ligament  to  terminate  in  the  external  iliac 
plexus. 

The  Epigastric  Absorbents  are  derived  from  the  inferior  an- 
terior parietes  of  the  abdomen,  along  the  region  of  distribution 
of  the  epigastric  artery.  Their  trunks  coalesce  into  larger  ones, 
and  descend  along  this  artery  to  end  in  the  external  iliac  plexus, 
near  the  crural  arch. 

The  Lumbar  Absorbents  arise  from  the  muscles  of  the  loins, 
from  the  posterior  part  of  those  of  the  abdomen,  and  from  the 
spinal  cavity.  Their  trunks  correspond  with  the  lumbar  arte- 
ries, and  passing  beneath  the  psoas  magnus  muscle  towards  the 
spine,  they  terminate  in  the  lumbar  glands. 

The  Intercostal  Absorbents  take  their  origin  from  the  parietes 
of  the  thorax,  and  following  the  course  of  their  respective  inter- 
costal arteries,  pass  through  some  small  glands  occasionally 
found  between  the  external  intercostal  muscles  near  the  heads 
of  the  ribs.  They  are  there  joined  by  trunks  from  the  spinal 
cavity  and  from  the  muscles  of  the  back,  and  afterwards  passing 
through  some  small  glands  on  the  front  of  the  vertebral  column, 
they  anastomose  more  or  less  with  one  another,  and  finally  ter- 
minate in  the  left  thoracic  duct.  The  absorbents  of  the  pleura 
costalis  and  of  the  posterior  part  of  the  pericardium  terminate 
in  the  intercostals. 

The  Internal  Mammary  Absorbents  have  their  roots  in  the 
anterior  region  of  the  parietes  of  the  abdomen,  above  the  umbi- 
licus, where  they  anastomose  with  the  epigastric.  They  ascend, 
along  with  the  internal  mammary  arteries,  behind  the  sternal 


ABSORBENTS  OF  THE  PARIETES  OF   THE  TRUNK.  309 

Cartilages,  pass  through  some  small  glands,  and  receive  contri- 
butions from  the  anterior  extremities  of  the  intercostal  spaces. 
Those  of  the  left  side,  assembling  into  one  or  two  trunks,  cross 
in  front  of  the  left  subclavian  vein,  traverse  the  inferior  cervical 
glands,  descend  afterwards  from  this  point,  and  terminate  in  the 
left  thoracic  duct,  or  in  one  of  the  contiguous  trunks  of  the  ve- 
nous system.  Those  on  the  right  execute  the  same  movements, 
but  terminate  in  the  right  thoracic  duct,  or  in  one  of  the  conti- 
guous venous  trunks  of  that  side. 

The  Absorbents  of  the  Diaphragm  are  exceedingly  numerous, 
and  very  much  connected  with  those  of  the  liver.  The  anterior 
ones  join  the  internal  mammary  absorbents,  while  the  posterior 
follow  the  phrenic  arteries,  or  go  to  contiguous  trunks  belonging 
to  the  intercostals.  The  front  ones  on  the  right  side,  then  ter- 
minate in  the  right  thoracic  duct,  while  the  remainder  go  in  the 
various  routes  of  the  absorbents,  with  which  they  are  connected, 
into  the  left  thoracic  duct.  They  are  principally  seen  on  its 
upper  surface.  Mr.  Cruikshank  *  says,  that  he  once  saw  them 
to  the  amount  of  three  hundred  or  more,  filled  with  chyle  from 
the  mesentery  that  had  passed  through  the  substance  of  the  liver. 
Asellius  was,  therefore,  probably  justified  by  an  accident  of  this 
kind,  in  asserting  that  the  lacteals  went  to  the  liver. 

The  Absorbents  of  the  Female  Mamma?,  like  their  arteries 
and  veins,  are  superficial  and  deep ;  the  former  attend  the  exter- 
nal thoracic  blood  vessels,  and  the  latter  the  internal  mammary. 
The  superficial  arise  from  the  circumference  of  the  nipple,  from 
the  skin  and  cellular  membrane,  and  according  to  the  injections 
of  Mr.  Cruikshank,  communicate  freely  with  the  vesicles  of  the 
tubuli  lactiferi.  They  run  towards  the  axilla,  having  sometimes 
to  pass  through  some  glands  which  are  situated  half  way ;  they 
then  enter  the  first  series  of  glands  of  the  axilla  in  their  direc- 
tion, and  afterwards  others  successively,  until  they  terminate  in 
the  lymphatic  trunks  of  the  upper  extremity,  high  up  in  the  arm- 
pit Some  few  of  these  superficial  vessels  ascend  over  the  pec- 
toralis  major  to  some  glands  in  the  neck,  just  above  the  clavicle. 

*  Loc.  cit.  p.  90. 
VOL.  II.-40 


CIRCULATORY  SYSTEM. 

The  deep  absorbents  of  the  mammae  arise  from  their  thoracic 
face,  and  penetrating  the  intercostal  spaces,  join  the  absorbents 
that  attend  the  internal  mammary  artery. 

\ 

Of  the  Absorbent  Glands  in  the  Thorax. 

There,  are,  as  mentioned,  a  few  small  glands  in  the  intercos- 
tal spaces  near  the  heads  of  the  ribs  between  the  internal  and  ex- 
ternal intercostal  muscles,  intended  to  receive  the  lymphatics 
of  these  spaces.  There  are  also  several  small  ones  situated  on 
the  front  of  the  dorsal  vertebrae,  along  the  aorta  and  the  oeso- 
phagus, in  the  posterior  mediastinum.  There  are  also  from  six 
to  ten  along  the  internal  mammary  artery;  and  some  others  in 
the  anterior  mediastinum,  along  the  sternal  face  of  the  pericar- 
dium. They  are  said  to  be  very  rarely  affected  by  disease. 

The  most  considerable  and  striking  glands  in  the  thorax  are 
those  called  Bronchial  or  Pulmonary,  which  receive  the  absor- 
bents of  the  lungs.  They  cluster  about  the  bifurcation  of  the 
trachea,  and  follow  the  bronchise  for  some  distance  into  the  sub- 
stance of  the  lungs.  They  are  from  ten  to  twenty  in  number, 
and  vary  in  size  from  an  inch  to  a  few  lines  in  diameter.  Till 
puberty  tlfey  have  a  reddish  colour,  -but  afterwards  they  be- 
come gray,  and  finally  black,  following  in  these  respects  the 
change  of  colour  in  the  lungs.  According  to  Mr.  Pearson, 
their  complexion  depends  upon  the  deposite  of  pure  carbon. 

In  pulmonary  consumption  these  glands  are  always  enlarged, 
and  look  scrofulous. 

SECT.  Yin. o~ OF  THE  THORACIC  DUCTS. 

The  Left  Thoracic  Duct  (Ductus  Thoracicus  Sinister]  is  the 
main  stream  of  the  absorbent  system,  to  which  almost  all  the 
others  are  but  tributary,  and  by  divers  routes  ultimately  find 
their  way  into  it.  It  begins  about  the  second  or  third  lumbar 
vertebra,  in  front  o^  its  body.  Shortly  after  its  commencement, 
while  still  in  the  abdomen,  it  suffers  a  dilatation  more  or  less 
considerable,  and  varying  in  its  shape  in  different  subjects. 
This  is  called  the  Reservoir  of  Pecquet,  or  the  Receptaculum 
'Chyli;  the  dilatation,  however,  is  frequently  absent,  and  does 


THORACIC  DUCTS.  311 

not  seem  to  be  an  essential  part  of  the  structure:  in  bur  pre- 
parations at  the  University  some  have  it,  and  others  Jiave  it 
not. 

The  thoracic  duct  enters  the  thorax  between  the  crura  of  the 
diaphragm,  to  the  right  of,  and  behind  the  aorta:  it  then  ascends 
on  the  front  of  the  dorsal  vertebrae,  between  the  aorta  and  the 
vena  azygos,  in  front  of  the  right  intercostal  arteries,  and  behind 
the  oasophagus.  At  the  fourth  dorsal  vertebra  it  begins  to  in- 
cline in  its  ascent  to  the  left  side,  and  then  ascends  into  the 
neck  near  the  head  of  the  first  rib;  it  rises  commonly  as  high 
up  as  the  upper  margin  of  the  seventh  cervical  vertebra;  it  then 
turns  downwards  and  forwards,  over  the  left  subclavian  artery 
within  the  scaleni  muscles,  and  finally  discharges  into  the  angle 
of  junction  of  the  left  subclavian  and  internal  jugular  veins. 

The  preceding  is  the  most  simple,  and  perhaps  the  most  com- 
mon form,  under  which  the  thoracic  duct  is  presented,  but  va- 
rieties are  continually  occurring  in  its  place  and  mode  of  origin, 
in  its  trunk,  and  its  manner  and  place  of  termination.  It  com- 
monly begins  by  the  union  of  three  absorbent  trunks;  one  for 
each  side  of  the  pelvis,  along  with  the  corresponding  lower  ex- 
tremity; and  a  middle  one  for  the  chyliferous  vessels,  which 
unites  with  the  common  trunk  of  the  other  two,  a  few  lines 
above  its  point  of  formation;  on  other  occasions,  the  chyliferous 
trunks  join  'it  in  a  confused  manner  by  nine  or  ten  distinct 
channels.  Sometimes  an  intricate  plexus  of  several  large  trunks, 
derived  from  the  lumbar  and  mesenteric  glands;  by  the  gradual 
reduction  of  the  number  of  meshes  from  the  successive  joining 
of  trunks;  begins  to  assume,  at  the  crura  of  the  diaphragm,  the 
form  of  a  solitary  trunk,  which  is  the  thoracic  duct.  The  trunk 
of  the  duct  is  also  disposed  to  keep  up  the  anastomosing  plan, 
even  in  the  thorax;  we  hence  see  it  sometimes  dividing  itself 
into  two  or  three  channels  of  equal  sizes,  which  unite  again  af- 
ter a  shorter  or  longer  distance,  and  perhaps  in  a  little  space 
repeat  the  same  arrangement:  sometimes  a  small  arm  is  sent 
off,  which  runs  alone  for  an  inch  or  two,  and  joins  into  the  pa- 
rent stream;  sometimes  spiral  turns  are  adopted  by  the  thoracic 
duct,  sometimes  nodosities,  or  small  pouches,  are  formed  on  its 
sides;  sometimes  it-is  dilated  at  intervals  in  its  whole  circumfe- 


312  CIRCULATORY  SYSTEM. 

rence.  Sometimes  it  splits  into  several  channels  at  its  termina- 
tion; one  channel  terminating  in  one  vein  and  another  in  a  con- 
tiguous one,  of  the  several  trunks  forming  the  vena  innominata; 
on  other  occasions,  instead  of  entering  into  a  venous  trunk 
of  the  left  side,  it  goes  into  the  corresponding  one  of  the  right. 

Commonly,  it  is  about  the  size  of  a  large  crow-quill,  but  some- 
times as  large  as  a  goose-quill,  or  even  still  more  voluminous, 
seeming  to  be  in  a  varicose  state,  of  which  Mr.  Cruikshank  men- 
tions an  example  where  it  was  half  an  inch  in  diameter,  and 
took  two  pounds  of  mercury  to  fill  it.  There  is  generally  a  pair 
of  valves  at  the  termination  of  the  thoracic  duct,  or  if  it  be  di- 
vided into  several  streams  there  is  a  pair  at  the  embouchure  of 
each,  to  keep  the  venous  blood  out  of  it.  There  are  also  valves 
in  its  length,  but  they  are  not  numerous,  and  vary  in  different 
subjects. 

The  thoracic  duct  is  the  grand  outlet  for  the  lymphatics  of  the 
left  side  of  the  head  and  neck,  of  the  left  superior  extremity,  of 
the  intercostals,  of  the  left  side  of  the  thorax,  of  the  viscera  of 
the  abdomen,  and  of  the  inferior  extremities.  Though  those  of 
the  viscera  of  the  abdomen  and  of  the  lower  extremities  have 
this  route,  yet,  from  the  observations  of  Mr.  Lippi,  of  Florence, 
as  mentioned,  they  have  also  some  more  direct  means  of  getting 
into  the  general  circulation.  For  example,  he  has  found  several 
large  lymphatic  trunks  emptying  into  the  ascending  cava,  one  of 
them  opposite  the  third  lumbar  vertebra;  another  into  the  primi- 
tive iliac  vein :  he  has  also  found  some  of  the  lympathics  of  the 
liver  discharging  into  the  vena  portarum. 

• 

The  Uight  Thoracic  Duct,  (Ductus  Thvracicus  Dexter,)  as  it 
is  called,  W  more  properly  the  Right  Brachio-cephalic,  after  the 
name  given  by  M.  Chaussier  to  the  vein,  is  not  more  than  an  inch 
long,  and  descends  to  empty  itself,  as  mentioned,  into  the  junc- 
tion of  the  right  internal  jugular  with  the  right  subclavian  vein. 
It  is  derived  from  the  lymphatic  trunks  of  the  right  side  of  the 
head  and  neck,  from  the  right  upper  extremity,  the  superficial 
lymphatics  of  the  right  side  of  the  thorax,  the  lymphatics  of  the 
right  lung,  of  the  right  side  of  the  diaphragm,  and  some  of  those 
of  the  right  side  of  the  liver,  the  courses  of  all  of  which  have 
been  detailed. 


THORACIC  DUCTS.  313 

Though  the  single  trunk  is  formed  from  these  several  tributary- 
streams,  yet  the  latter  have  sometimes  several  embouchures  into 
the  venous  system  at  or  near  the  point  mentioned,  and,  as  on 
the  other  side  of  the  body,  there  is  a  proper  security,  by  valves, 
from  the  introduction  of  blood  into  them. 

There  is  always  an  ample  system  of  anastomosis,  not  only  be- 
tween the  branches  which  concur  to  form  the  right  and  left  tho- 
racic ducts,  but  even  between  the  ducts  themselves,*  so  that  if 
one  be  occluded  or  impeded,  its  circulation  can  be  turned  into 
the  other,  as  in  the  case  of  veins. 

*  Meckel,  Man.  D'Anat.  torn.  ii.  p.  581. 


BOOK  IX. 

PART  I. 

Of  the  General  Anatomy  of  the  Nervous  System. 
NERVOUS  SYSTEM. 

THE  nervous  system  in  man,  and  other  vertebrated  animals, 
consists  in  two  portions  of  dissimilar  forms  :  one  is  spheroidal, 
elongated  at  its  base  into  a  cylindrical  process,  and  is  contained 
in  the  cranium  and  in  the  spinal  canal;  the  other  is  an  assem- 
blage of  arborescent  rays,  which  proceed  from  different  points  of 
the  first  portion,  to  every  part  of  the  body.  The  first  portion  is 
the  Central  or  Internal  part  of  the  nervous  system,  composed  of 
the  Brain  and  Spinal  Marrow,  while  the  radiating  portion  is 
called  the  External  or  Peripheral,  and  consists  in  the  Nerves  of 
the  brain  and  spinal  marrow. 

The  nervous  system  is  remarkable  for  its  symmetry ;  as  it  is 
universally  double,  it  very  seldom  happens  that  any  striking  dif- 
ference of  it  on  the  two  sides  of  the  body  is  manifested,  particu- 
larly as  regards  its  Central  portion;  it  is  said,  however,  that 
aberrations,  in  this  respect,  are  more  common  in  man  than  in 
other  mammiferous  animals. 

The  Central  Portion  of  the  Nervous  System  is  composed  of 
two  kinds  of  substance,  distinguished  by  their  colour  and  rela- 
tive situation :  one  is  improperly  enough  called  Medullary,  (Sub- 
stantia  MedullarisJ  but  as  the  name  is  now  sanctioned  by  uni- 


316  NERVOUS  SYSTEM. 

versal  usage,  it  is  impossible  to  dispense  with  it.  The  other  is 
called  Cineritious,  (Substantia  Cinerea,)  with,  perhaps,  sufficient 
propriety,  from  its  colour.  They  are  both  of  a  soft  pulpy  con- 
sistence, and  constitute  the  chief  mass  of  the  brain  and  spinal 
marrow:  some  anatomists  have  desired  to  add,  from  some  slight 
distinction  of  colour,  two  other  substances,  a  yellow  and  a  black, 
but  that  seems  unnecessary,  and  has  not  been  acknowledged. 
These  substances  differ  from  one  another  in  regard  to  their 
quantity,  the  medullary  being  more  abundant  than  the  cineri- 
tious ;  it  is  also  harder,  and  receives  fewer  vessels.  But  the 
atoms  of  both  have  the  same  elementary  form,  that  of  globules 
united  by  a  semi-fluid  substance ;  the  shape  of  these  globules,  as 
well  as  their  size  and  degree  of  solidity,  are  not  yet  ascer- 
tained.* 

The  Medullary  Matter,  when  quite  fresh  and  scraped  in  par- 
ticular directions,  has  a  fibrous  appearance,  which  may  be  ren- 
dered still  more  distinct  by  hardening  it  in  alcohol,  in  boiling  oil, 
in  a  solution  of  the  neutral  salts,  or  in  diluted  mineral  acids.  If 
an  attempt  be  then  made  to  tear  it,  it  will  be  immediately  per- 
ceived that  the  fibres  separate  in  a  fixed  direction,  and  in  no 
other.  These  fibres,  when  viewed  with  a  microscope,  seem  to 
consist  of  fibrillae  too  fine  to  admit  of  any  rigid  conclusions  in 
regard  to  their  size ;  and  which  are,  in  some  instances,  parallel, 
in  others,  concentric,  and  in  others,  diverging  or  converging.! 

The  two  substances  are  variously  placed  in  different  parts  of 
the  nervous  system :  the  surface  of  the  cerebrum  and  of  the  ce- 
rebellum is  formed  by  the  cineritious  matter,  and  the  interior 
principally  of  medullary ;  while  the  surface  of  the  pons,  of  the 
crura,  and  of  the  spinal  marrow,  is  medullary,  and  their  interior 
cineritious.  Again,  in  other  points,  they  are  intermixed.  The 
medullary  matter  is  always  so  arranged  that  it  is  never  inter- 
rupted, but  forms  a  continuous  whole ;  while  the  cineritious  is  in 
detached  masses,  and  is  found  wherever  the  central  extremities 
of  the  nerves  are  implanted,  or  where  there  is  an  increase  of 

*  Sir  Everard  Home,  and  M.  Bauer,  Phil.  Transactions.  London,  An.  1821. 
Milne  Edwards,  Thesis  on  the  Elementary  Tissues  of  Animals.  Paris,  1823. 

f  See  Lessons  on  Practical  Anatomy,  by  W.  E.  Homer,  for  description  of 
Brain  according  to  Gall  and  Spurzheim. 


GENERAL  ANATOMY  OF  THE  NERVOUS  SYSTEM.  317 

medullary  fibres.  Some  anatomists  have  even  supposed  that  it 
existed  at  the  peripheral  extremities  of  the  nerves,  and  particu- 
larly in  the  rete  mucosum  of  the  skin. 

The  fibrillae  of  the  medullary  tissue  are  united  by  a  very  fine 
and  thin  cellular  substance,  which  may  be  seen  by  tearing  them 
apart.  This  cellular  substance  is  more  condensed  near  the  sur- 
face of  the  brain,  where  it  is  formed  into  a  highly  vascular  mem- 
brane, the  pia  mater,  and  is  continued  along  the  nerves  as  a  neu- 
rileme,  or  covering  to  them. 

The  central  nervous  system  is  abundantly  supplied  with 
blood  vessels,  but  lymphatic  trunks  have  not  yet  been  injected 
in  it. 

The  Peripheral  Portion  of  the  Nervous  System  or  the  Nerves, 
are  formed  by  parallel  anastomosing  fasciculi  of  fibres,  percep- 
tible to  simple  inspection,  which  may  be  reduced  into  fibrillae, 
and  then  again  into  filaments  as  small  as  the  thread  of  a  silk 
worm.  The  finest  filament  is  enclosed  in  its  appropriate  sheath, 
so  that  the  latter  is  a  tube  filled  with  nervous  matter.  The  ner- 
vous matter  is  soluble  in  an  alkali,  and  in  that  way  may  be  re- 
moved; the  canals  may  then  be  filled  with  quicksilver  or  air, 
and  their  existence  demonstrated.  On  the  other  hand,  nitric 
or  muriatic  acid  dissolves  the  sheath,  but  hardens  the  nervous 
matter,  and  renders  it  more  distinct,  so  that  the  finest  filaments 
are  made  obvious.*  In  either  case  it  is  evident  that  the  shape 
of  the  nerve  is  preserved.  These  filaments  are  supposed  to  be 
precisely  the  same  with  the  fibres  of  the  brain,  excepting  that 
their  sheaths  keep  them  more  distinct  from  one  another. 

The  Sheath  of  the  nerves,  or  the  Neurileme  (Neurilemma) 
forms  a  general  envelope  to  the  nervous  fasciculi,  as  well  as  a 
particular  one  to  each  fibre,  and  is  continuous,  at  its  central  ex- 
tremity, with  the  pia  mater.  Its  canals  branch  off  and  unite 
again  at  intervals,  forming  a  species  of  reciprocal  anastomosis, 
sufficiently  represented  by  the  plan  of  the  large  nervous  plex- 
uses, -as  they  occur  in  various  parts  of  the  body.  It  is  the  ge- 
neral envelope  which  is  obviously  continuous  with  the  pia  ma~ 

*  Reil,  de  Struct.  Nerv. 
VOL.  II.— 41 


318  NERVOUS  SYSTEM. 

ter,  but  the  particular  sheaths  of  the  finer  fibres  are  lost  insen- 
sibly, so  that  these  fibres  appear  naked  in  the  centre  of  the 
nerve,  at  its  central  extremity.  The  same  destitution  of  neu- 
rilematic  covering  is  observable  at  the  peripheral  extremities  of 
the  nerves,  wherever  the  latter  can  be  traced.  The  interior  of 
these  canals  is  traversed  by  processes,  which  cross  the  nervous 
matter  and  sustain  it.  From  the  increase  in  size,  the  additional 
solidity,  and  the  close  adhesion  of  the  nerves  to  the  dura  ma- 
ter, where  they  pass  out  of  their  several  foramina  in  the  spine 
and  cranium,  there  is  no  doubt  that  the  dura  mater  contributes 
to  the  neurileme,  though  its  structure  is  altered  and  made  much 
less  dense.  The  best  evidence  of  this  is  the  sheath  of  the  optic 
nerve,  and  of  the  spinal  nerves.  This  opinion,  advanced  by  the 
ancients,  has  been  strongly  contested  by  Haller,*  and  by  Zinn.t 
The  tunica  arachnoidea  is  too  fine  to  admit  of  any  positive  opi- 
nion about  the  extent  to  which  it  follows  the  nerves. 

The  neurileme  has  but  little  contractility,  is  solid  and  diffi- 
cult to  tear,  and  is  supposed  to  be  the  secretory  organ  of  the 
medullary  substance. 

The  nervous  fasciculi  are,  moreover,  held  together  by  cellu- 
lar substance,  which  has  in  the  progress  of  life,  a  tendency  to 
the  deposite  of  fat.  This  cellular  substance,  in  neuralgic  affec- 
tions, is  subject  to  infiltrations  and  redness,  whereby  it  becomes 
hard.  This  circumstance  has  induced  pathologists  to  consider 
the  pain  as  depending  upon  its  inflammation.^ 

The  optic  nerve,  owing  to  the  size  of  its  canals,  furnishes  the 
best  example  of  structure,  and  the  nerves  of  the  muscles  are 
next.  There  are,  however,  some  peculiarities  in  different  nerves; 
as  the  observations  of  Sir  Everard  Home  have  ascertained  that 
the  medullary  filaments  of  the  optic  nerve  augment  in  numbers 
and  diminish  in  volume,  from  its  origin  towards  its  termina- 
tion. The  principal  light  thrown  upon  these  minute  and  inte- 
resting points  of  nervous  organization,  has  been  derived  from 
the  researches  of  Reil.§ 

In  addition  to  the  preceding  structure,  the  nerves  present  a 
satin-like  undulated  surface,  with  small  bands  that  pass  some- 

*  Prim.  Lin.  •[  Memoires  de  Berlin,  1753. 

*  Beclard,  Anat.  Gen.  p.  665. 

§  Reil,  de  Structure  Nervorum.     Halx  Saxonum,  1796. 


GENERAL  ANATOMY  OP  THE  NERVOUS  SYSTEM.  319 

what  spirally  and  in  a  zigzag  direction.  The  latter  appearance 
is  illusory,  and  depends  upon  the  contraction  or  shortening  of 
the  nerve  when  not  stretched;  its  seat  is  in  the  neurileme,  and 
it  accordingly  disappears  upon  extension. 

The  nerves  abound  in  blood  vessels;  when  a  vascular  trunk 
reaches  them,  one  of  its  branches  ascends  and  another  descends, 
and  if  successfully  injected,  the  neurileme  is  covered  by  its  ca- 
pillary ramifications.  As  in  the  brain,  the  lymphatics  have  not 
yet  been  injected. 

There  are  three  modes  by  which  the  nervous  fasciculi  unite 
with  one  another;  anastomosis,  plexus,  and  ganglion.  Anasto- 
mosis is  the  junction  of  the  filaments,  either  of  the  same  nerve 
or  of  different  nerves,  and  the  examples  of  it  are  very  abun- 
dant. Plexus  is  an  anastomosis  on  a  larger  scale,  and  occurs 
between  the  larger  fasciculi  of  the  same  nerve,  or  of  different 
nerves,  whereby  a  very  complete  intertexture  of  their  fibres 
occurs. 

Ganglions  are  knots  which  occur  in  the  course  of  nerves 
whereby  they  have,  for  the  time,  a  great  augmentation  of  vo- 
lume. The  ganglions  have  a  great  variety  of  form  and  size; 
they  are  parabolic,  circular,  crescentic  and  so  on;  and,  in  their 
general  appearance,  hardness,  and  colour,  resemble  somewhat 
lymphatic  glands.  Their  structure  is  intricate,  and  as  yet  ra- 
ther unsettled.  When  submitted  to  maceration,  they  are  re- 
solved into  two  kinds  of  substance;  one  is  filamentous  and 
continuous  with  the  nerves  adhering  to  the  ganglion,  and  the 
other  is  gelatinous  and  of  a  reddish  ash  colour.  The  filaments, 
in  penetrating  the  ganglions  are  deprived  of  their  neurileme, 
which  is  continued  into  a  sort  of  capsule  that  surrounds  the  gan- 
glions. They  pass  uninterruptedly  through  the  ganglion,  and, 
therefore,  continue  the  several  nervous  cords  into  one  another; 
but  in  a  complicated  way.  The  nature  of  the  gelatinous  sub- 
stance is  not  fully  ascertained;  by  some,  and  Scarpa  among 
others,  it  is  thought  to  be  fat.  The  ganglions,  like  other  parts 
of  the  nervous  system,  are  very  vascular. 

The  Ganglions  are  said  to  be  simple  and  compound;  the  first 


320  NERVOUS  SYSTEM. 

is  where  a  single  nerve  produces  the  ganglion,  and  the  second 
where  the  filaments  of  two  or  more  nerves  concur  to  form 
it.  The  simple  ganglions  are  invariable  in  their  form  and  si- 
tuation, and  belong  to  the  spinal  marrow,  being  formed  upon 
the  posterior  fasciculi  alone:  this  fact  was  first  pointed  out  by 
Haase,*  and  has  been  subsequently  confirmed  by  the  obser- 
vations of  Scarpa  and  of  Prochaska  and  by  the  admission  of 
anatomists  generally.  The  exterior  envelope  is  continuous 
with  the  dura  mater,  and  the  internal  with  the  pia  mater,  from 
whence  they  have  more  firmness  than  other  ganglions.  The 
composite  ganglions  are  found  at  divers  stations  about  the 
body. 

The  Nervous  system  is  the  seat  of  intelligence,  and  also 
extends  its  physical  influence  to  every  part  of  the  body.  Both 
the  one  and  the  other  qualities  reside  in  its  central  portion; 
the  first  in  the  brain,  and  the  second  in  the  spinal  marrow. 
When  the  communication  between  the  brain  and  the  spinal 
marrow  is  interrupted  by  an  accident,  or  in  an  experiment, 
the  difference  between  the  influence  of  the  two  is  strongly 
marked:!  the  influence  of  the  brain  seeming  to  be  entirely  in- 
tellectual, so  that  an  animal  will  even  bear  its  removal  with- 
out immediate  death;  while  the  influence  of  the  spinal  mar- 
row is  so  indispensable  to  life,  that  its  destruction  is  followed 
by  instantaneous  and  perfect  death.J  Under  common  health- 
ful circumstances,  however,  the  two  seem  to  exercise  a  mixed 
influence  on  all  parts  of  the  body;  as,  for  example,  upon  the 
reception  of  distressing  intelligence,  the  stomach  ejects  its  con- 
tents, or  refuses  to  receive  more;  alarming  intelligence  causes 
the  heart  to  flutter  and  to  palpitate,  and  both  the  bladder  and 
the  intestines  to  evacuate  their  contents.  On  the  contrary,  a 
proper  degree  of  corporeal  exertion  strengthens  the  intellec- 
tual operations,  while  its  excess  debilitates  them.  That  these 
several  nervous  influences  are  seated  in  the  central  part  of  the 

*  De  Gangliis  Nervorum.     Leipsick,  1772. 
-j-  Legallois  on  the  Principle  of  Life. 

$  Observ.  and  Exper.  on  the  Nervous  System,  by  W.  E.  Hofner.  See  Chap- 
man's Med.  and  Phys.  Journal,  vol.  i.  p.  285, 


GENERAL  ANATOMY  OF  THE  NERVOUS  SYSTEM.  321 

nervous  system,  seems  proved  by  the  fact,  that  where  there 
has  been  a  congenital  deficiency  of  all  the  limbs,  or  an  ac- 
cidental one,  which,  of  course,  removes  a  very  considerable 
portion  of  the  peripheral  part  of  the  nervous  system,  animal 
life  and  the  intellectual  operations  have  still  gone  on  vigo- 
rously. 

The  following  are  some  of  the  physical  functions  over  which 
the  nervous  system  seems  to  preside. 

Digestion;  the  whole  alimentary  canal,  from  the  mouth  to  the 
anus,  is  under  this  influence :  first  of  all  in  mastication,  then  in 
swallowing,  afterwards  in  digestion  and  the  absorption  of  chvle, 
and,  finally,  in  the  passing  of  the  effete  matter  out  of  the  body. 
It  has  been  sufficiently  proved,  by  the  experiments  of  several 
physiologists,  that  the  section  of  the  par  vagum  destroys  the 
faculty  of  digestion. 

Respiration ;  the  mechanical  act  of  this  process,  that  by  which 
the  cavity  of  the  thorax  is  enlarged  so  as  to  admit  of  the  intro- 
duction of  air,  evidently  depends  upon  the  phrenic  and  the  in- 
tercostal nerves.  If  the  nerves  which  supply  the  structure  of 
the  lungs  be  alone  intercepted,  as  the  par  vagum,  either  by  liga- 
ture or  section,  the  changes  on  the  blood  produced  by  respiration 
cease,  and  the  animal  dies. 

Secretion,  exhalation,  absorption,  and  animal  heat,  seem  also 
to  be  dependent  upon  the  integrity  an'd  the  activity  of  nervous 
influence.  The  action  of  the  heart,  sensation  and  voluntary  mo- 
tion, are  in  the  same  predicament. 

The  manner  in  which  these  several  kinds  of  innervation  is 
produced,  is  unintelligible.  One  has  supposed  it  to  consist  in  a 
vibration  of  the  elementary  fibres'  of  the  nerves ;  another  in  an 
agitation  of  its  elastic  globules ;  another  in  the  transmission  of  an 
imponderable  fluid,  as  ether,  magnetism,  electricity,  and  Galva- 
nism. Reil  has  proposed,  on  this  subject,  what  has  been  termed 
a  chemico-vital  hypothesis:  according  to  him,  the  general  action 
of  parts  depends  upon  their  form  and  composition  ;  consequently, 
when  the  two  latter  vary,  the  first  does  also.  M.  Beclard*  in- 
clines to  the  opinion,  that  "  the  nervous  system  is  the  elaborator 
and  conductor  of  an  imponderable  agent ;  and,  like  electricity 

*  Anat.  Gen. 


322  NERVOUS  SYSTEM. 

or  magnetism,  that  by  it  we  can  explain  all  the  phenomena  of 
innervation: — The  relation  between  the  benumbing  influence  of 
electric  fish  and  Galvanic  phenomena  on  one  part,  and  ordinary 
nervous  action  on  the  other; — The  practicability  of  causing 
Galvanic  phenomena  by  the  nerves  and  muscles  alone; — The 
possibility  of  producing  muscular  contraction,  the  chymifiant  ac- 
tion of  the  stomach,  the  respiratory  action  of  the  lung,  &c.,  in 
substituting  a  Galvanic  for  a  nervous  influence ; — The  existence 
of  a  nervous  atmosphere,  acting  at  a  distance  around  the  nerves 
and  muscles,  and  between  the  ends  of  divided  nerves; — The 
wrinkling  of  muscular  fibres  in  contraction,  and  the  relation  of 
the  finest  transverse  nervous  fibres  with  those  wrinkles,  are  phe- 
nomena of  innervation  which  nearly  approach  certain  electro- 
magnetical  ones." 

This  subtile  fluid,  according  to  M.  Be  clard,  seems  to  be  formed 
every  where,  but  principally  in  places  where  there  is  much  vas- 
cularity  along  with  the  ash-coloured  substance.  It  impregnates 
all  the  humours  and  organs.  The  blood  seems  to  be  especially 
endowed  with  it,  and  owes  to  it  the  properties  which  distinguish 
it  during  life.  In  consequence  of  which,  life  is  essentially  con- 
nected to  the  reciprocal  action  of  the  blood  upon  the  nervous 
substance,  and  of  the  nervous  substance  upon  the  blood.* 

Mr.  Charles  Bell,  of  London,  has  lately  presented,  in  a  very  in- 
teresting light,  certain  functions  of  the  nervous  system:!  by  his 
researches  it  appears,  that  besides  the  nerves  of  vision,  smell, 
and  hearing,  there  are  four  other  systems,  having  different  func- 
tions, and  extended  through  the  whole  frame.  Those  of  Sensa- 
tion ;  of  Voluntary  Motion ;  of  Respiratory  Motion ;  and  nerves, 
which  give  unity  to  the  body  in  harmonizing  the  functions  of 
nutrition,  growth,  and  decay,  or  whatever  else  is  indispensable 
to  animal  existence. 

*  M.  Rolando  (Saggio  sulla  vera  struttura  del  cervello,  e  sopra  le  funzioni  del 
sistema  nervoso,  1809,  Beclard,  p.  622,)  has  been  so  much  taken  with  the  Gal- 
vanic manifestations  of  the  nervous  system,  that  in  the  laminated  arrangement  of 
the  cerebellum,  he  has  only  seen  a  modification  of  the  Voltaic  pile'.  In  the  con- 
volutions of  the  cerebrum,  he,  no  doubt,  would  have  recognised  an  acquaintance 
with  that  powerful  instrument,  the  Spiral  Calorimotor  of  Professor  Hare  of  this 
University. 

f  Exposition  of  the  Natural  System  of  the  Nerves  of  the  Human  9ody.  Philad. 
1825. 


GENERAL  ANATOMY  OF  THE  NERVOUS  SYSTEM.  323 

According  to  this  theory,  the  several  filaments  of  a  nerve 
exercise  one  or  the  other  function,  but  only  tfie  one ;  these  dis- 
similar filaments  being  bound  up  in  the  same  fasciculus,  con- 
stitute a  nerve  or  fascis,  and  they  never  exchange  power  with 
one  another:  their  anatomical  differences,  however,  are  such,  as 
not  to  make  obvious  one  kind  of  filaments  from  the  others.  Se- 
veral columns  of  nervous  matter  form  the  spinal  marrow,  six  in 
all,  three  on  each  side ;  the  anterior  for  voluntary  motion,  the 
posterior  for  sensation,  and  the  middle  for  respiration;  and  it  is 
probable  that  still  more  may  be  found  out.  The  first  and  the 
third  ascend  into  the  brain,  and  the  middle  stops  short  in  the 
medulla  oblongata;  hence,  the  function  of  respiration  goes  on  so 
long  as  the  medulla  oblongata  remains  entire.  These  few  prin- 
ciples, supported  by  several  experiments,  have  enabled  Mr.  Bell 
to  bring  forward  a  system  of  no  small  importance  on  the  anatomy 
and  physiology  of  the  nervous  system.* 

The  development  of  the  nervous  system  is  amongst  the  earliest 
processes  in  the  distinct  evolution  of  the  foetal  organs.!  At  the 
end  of  the  first  month,  when  the  head  is  a  mere  swelling  of  one 
end  of  the  small  maggot-like  being,  the  brain  and  the  spinal 
marrow  are  not  by  any  means  distinct,  but  the  parts  being  trans- 
parent, a  limped  fluid  holds  their  place.  About  the  fifth  or  sixth 
week,  the  embryo  having  acquired  a  length  of  five  or  six  lines, 
the  rudiments  of  the  brain  appear  as  vesicles  containing  a  whitish 
and  almost  diaphanous  fluid,  while  the  spinal  marrow  represents 
a  long  canal  containing  the  same,  and  communicating  with  the 
cerebral  vesicles. 

In  the  early  part  of  the  third  month,  the  brain  and  spinal  mar- 
row show  very  distinctly  the  rudiments  of  the  several  cavities, 
elevations,  and  fasciculi,  which  mark  their  subsequent  mechanical 
arrangement  of  surface ;  and  from  this  period  it  is  no  longer  dif- 
ficult to  trace  the  successive  development  of  each  part  to  the 
degree  of  perfection  which  it  has  at  the  time  of  birth. 

*  The  same  subject  has  been  taken  up,  in  an  inaugural  thesis,  by  a  zealous  and 
intelligent  graduate  of  the  University;  and,  by  a  series  of  ingenious  experiments, 
seems  to  have  been  generally  proved  and  illustrated.  Chapman's  Med.  and 
Phys.  Journal,  1823,  vol.  vi.  p.  240.  Remarks  on  some  of  the  Nervous  Func- 
tions, by  J.  P.  Hopkinson,  M.  D. 

f  Anat.  du  Cerveau,  par  F.Tiedemann,  traduit  par  Jourdan,  Paris,  1823,  Anat. 
Comp.  du  Cerveau,  par  E.  R.  A,  Serres,  Paris,  1824. 


324  NERVOUS  SYSTEM. 

From  the  many  observations  made  by  Tiedemann  on  these 
points,  he  has  deduced  the  conclusion,  that  the  brain  is  produced 
by  the  superior  part  of  the  spinal  marrow;  that  is  to  say,  by  the 
medulla  oblongata,  which  grows  and  is  developed  for  the  pur- 
pose. That  this  is  proved,  in  the  extension  upwards  and  for- 
wards of  the  two  principal  fasciculi  of  the  spinal  marrow,  and 
by  a  canal  which  is  found  in  the  spinal  marrow  of  the  foetus, 
being  extended  to  the  fourth,  and  even  to  the  third  ventricle; 
also,  by  the  cerebellum  proceeding  evidently  from  the  medulla 
spinalis,  since  its  two  crura  may  be  traced  growing  from  it,  and 
subsequently  uniting  over  the  fourth  ventricle,  so  as  to  form  the 
especial  structure  of  the  cerebellum;  also,  by  the  tubercula 
quadrigemina  being  derived  from  the  corpora  olivaria  of  the  me- 
dulla oblongata,  and  by  the  thalami  and  the  corpora  striata  pro- 
ceeding from  the  corpora  pyramidalia,  and,  finally,  forming  the 
hemispheres  of  the  cerebrum. 

In  addition  to  the  preceding  proofs,  comparative  anatomy  fur- 
nishes other  illustrations.  The  brain  becomes  more  and  more 
complex  as  one  ascends  from  fish  to  reptiles,  from  the  latter  to 
birds,  and  then  to  jnammiferous  animals.  The  spinal  marrow 
is  very  voluminous  in  the  inferior  animals,  while  the  brain  only 
forms  an  appendix  to  it ;  whereas,  if  the  spinal  marrow  were  an 
appendix  to  the  brain,  we  ought  to  find  the  last  of  a  prior  forma- 
tion in  fetuses,  and  also  in  a  perfect  state  in  the  lower  animals, 
before  a  medulla  spinalis  could  be  found.* 

*  Tiedemann,  loc.  cit  p.  157. 


BOOK  IX. 


PART  II. 

On  the  Special  Anatomy  of  the  Central  portion  of  the  Nervous  System. 

CHAPTER  I. 

OF  THE  SPINAL  MARROW  AND  ITS  MEMBRANES. 

THE  Spinal  Marrow,  (Medulla  Spinalis)  though  commonly 
described  after  the  brain,  as  a  continuation  or  appendage  of  it, 
has  precedence,  as  seen,  both  in  the  period  of  its  formation  in 
the  embryo,  and  in  its  importance  to  the  functions  of  the  ani- 
mal system;  it  will,  consequently,  be  useful  to  give  it  that  prio- 
rity in  description  to  which  its  natural  rank  entitles  it. 

SECT.  I. OF  THE  SPINAL  MARROW. 

It  is  placed  within  the  vertebral  cavity,  and  extends  from  the 
first  vertebra  of  the  neck  to  the  first  or  second  vertebra  of  the 
loins,  inclusively.  It  is  surrounded  by  three  membranes,  of 
which  the  Dura  Mater  is  external,  the  Pia  Mater  internal,  and 
the  Tunica  Arachnoidea,  between  the  other  two.  Its  general 
form  is  cylindrical,  yet  it  has  slightly  the  appearance  of  being 
flattened  both  behind  and  before.  It  departs  also  from  the  strict 
cylindrical  shape,  by  being  enlarged  or  swollen  at  particular 
points.  One  of  these  enlargements  occurs  in  the  neck,  where 
the  canal  is  formed  by  the  five  lower  cervical  vertebras,  and  the 
axillary  plexus  of  nerves  is  given  off.  The  enlargement  is  i« 
VOL.  IL— 42 


326  NERVOUS  SYSTEM. 

the  transverse  direction  or  axis  of  the  spinal  marrow,  but  not 
so  much  in  its  thickness,  and  terminates  gradually  both  above 
and  below.  The  medulla  spinalis  afterwards  continues  small, 
with  very  slight  undulations  or  nodosities,  until  within  three  or 
four  inches  of  its  lower  extremity,  when  it  again  enlarges. 
The  enlargement  here,  though  sufficiently  obvious,  is  not  equal 
in  actual  magnitude  to  that  in  the  neck,  and  is  the  place  from 
which  all  the  lumbar  nerves  and  the  three  superior  sacral  pro- 
ceed. It  is  then  brought  gradually  to  a  point  somewhat  blunt- 
ed, which  most  commonly  does  not  descend  below  the  first  lum- 
bar vertebra.  The  point  is,  in  some  rare  cases,  bifurcated,  and 
by  a  transverse  fissure  converted  into  a  tubercle. 

The  spinal  marrow,  besides  terminating  so  much  above  the 
lower  end  of  the  spinal  canal,  is  much  smaller  in  its  diameter, 
even  with  the  addition  of  its  membranes,  than  the  canal.  This 
circumstance  prevails,  especially  in  the  neck,  and  in  the  loins, 
where  much  motion  is  experienced;  and,  consequently,  a  provi- 
sion is  thus  made  against  any  injury  to  it  from  pressure. 

• 

The  Medulla  Spinalis  is  marked  off,  longitudinally,  into  two 
symmetrical  parts,  by  one  fissure  in  front  and  another  behind, 
both  of  which  extend  its  whole  length,  and  are  placed  exactly 
in  its  middle.  The  contiguous  edges  or  surfaces  of  each  of  these 
fissures  adhere  so,  that  it  requires  a  slight  maceration  or  dissec- 
tion to  render  them  evident.  The  posterior  fissure  is  decidedly 
deeper,  especially  at  its  upper  part,  than  the  anterior;  but  the 
latter,  in  return,  is  somewhat  broader.  The  difference  in  depth, 
however,  is  unimportant,  as  subjects  are  frequently  met  with  in 
which  it  is  not  appreciable. 

Moreover,  on  each  side  of  the  medulla  spinalis  there  is  a  la- 
teral fissure.  It  is  not  precisely  in  the  middle,  but  somewhat 
posterior,  and  penetrates  inwards  and  forwards.  In  many  in- 
stances it  is  merely  a  simple  superficial  depression,  much  less 
deep  than  either  of  the  former.  It  does  not  run  the  whole  length 
of  the  medulla  spinalis,  but  terminates  somewhere  in  the  upper 
part  of  its  thoracic  portion  by  joining  with  its  fellow  after  having 
converged  regularly  towards  it.*  The  different  opinions  of  ana- 

*  Meckel,  Manuel  D'Anatomie. 


SPINAL  MARROW.  32? 

tomists  on  the  existence  of  this  fissure  may  be  accounted  for 
by  its  being  readily  found  in  early  life,  while  it  is  obliterated 
or  very  indistinct  in  old  age.  This  lateral  fissure  should  be  care- 
fully distinguished  from  two  others,  one  before  and  the  other 
behind  it,  which  extend  the  whole  length  of  the  medulla  spina- 
lis,  and  consist  in  a  series  of  little  depressions,  running  into 
each  other  and  transmitting  the  filaments  which  form  the  roots 
of  the  spinal  nerves.  The  posterior,  of  the  last  named  lateral 
fissures,  is  deeper  than  the  anterior,  and  penetrates  in  the  same 
direction  with  the  lateral  fissures  first  mentioned;  it  also,  in  like 
manner,  joins  its  fellow,  but  only  after  having  proceeded  to 
within  a  few  lines  of  the  inferior  end  of  the  medulla  spinalis. 

The  substance  of  the  spinal  marrow  being  of  two  kinds,  ci- 
neritious  and  medullary,  the  order  of  their  position  is  reversed 
from  what  occurs  in  the  brain;  for  the  cineritious  is  included  or 
enveloped  by  the  other.  On  making  a  transverse  section  the 
cineritious  will  be  found  much  less  abundant  than  the  other, 
and  consisting  of  a  thin  transverse  part  in  or  near  the  centre  of 
the  medulla.  This  part  is  joined  at  either  end  to  a  portion 
somewhat  crescentic,  whose  concavity  is  outwards,  and  the  con- 
vexity inwards.  The  transverse  part  does  not  run  into  the 
middle  of  the  crescent,  but  somewhat  anterior  to  the  middle,  so 
that  the  anterior  horn  is  shorter  than  the  other,  and  is  also 
thicker  and  obviously  more  obtuse.  The  cineritious  or  grayish 
substance  is  more  abundant  at  the  lower  part  of  the  medulla 
spinalis  than  it  is  above.  In  the  foetus,  at  the  end  of  gestation, 
it  predominates  below,  occasionally,  to  the  entire  exclusion  of 
the  other.  The  medullary  or  white  substance  is  more  abundant 
laterally  than  elsewhere,  and  has  its  two  symmetrical  sides 
joined  together  by  a  thin  lamina  at  the  bottom  of  the  anterior 
and  of  the  posterior  fissure. 

Each  half  or  symmetrical  side  of  the  medulla  spinalis  is  itself 
divided  into  two  chords,  marked  off  from  each  other  by  the  pos- 
terior horn  of  the  cineritious  crescent,  and  by  the  first  described 
lateral  fissure.  Of  these  chords  the  anterior  is,  consequently, 
much  the  larger;  it  is  also  longer  and  forms  the  inferior  extre- 
mity or  the  point  of  the  medulla  spinalis.  The  posterior  chord, 
though  so  much  smaller  and  narrower  than  the  anterior,  is  it- 


S28  NERVOUS  SYSTEM. 

self  subdivided  into  two,  by  a  slight  but  well  marked  split;  of 
the  two  last  chords,  the  one  next  to  the  posterior  middle  fissure 
of  the  medulla  is  smaller  than  the  other.  These  arrangements, 
according  to  Meckel,  are  much  more  obvious  in  the  early  life 
of  the  human  subject,  than  afterwards,  and  are  particularly  con- 
spicuous in  the  brute  creation. 

The  thin  white  laminae  by  which  the  two  sides  of  the  spi- 
nal marrow  adhere  to  each  other  at  the  bottom  of  the  middle 
fissures,  are  called,  by  modern  anatomists,  Anterior  and  Poste- 
rior Commissures.  Their  precise  arrangement  is  not  yet  fully 
ascertained,  but  it  is  stated  by  Gall  and  Spurzheim,*  that  the 
Anterior  Commissure  is  formed  by  transverse  fibres  or  filaments, 
which  adhere  to  one  another  from  the  opposite  sides  like  a  su- 
ture, or  after  a  serrated  fashion;  whereas,  the  Posterior  Com- 
missure is  formed  by  a  band  of  longitudinal  fibres.  There  is 
also  another  Commissure,  called  Middle  or  Cortical,  from  its 
position,  and  from  its  being  formed  out  of  the  transverse  part  of 
the  grayish  or  cineritious  substance. 

The  chords  which  form  each  half  of  the  medulla  are  different- 
ly disposed:  the  posterior  continues  on  the  side  to  which  it 
specially  belongs,  while  the  anterior  having  got  within  the  cir- 
cumference of  the  first  cervical  vertebra,  crosses  over  to  the  op- 
posite side  by  decussating  with  its  fellow.  This  decussation 
occupies  the  space  of  four  or  five  lines,  and  interrupts,  for  that 
distance,  the  middle  fissure  in  front  of  the  medulla.  It  is  not 
effected  by  the  chords  passing  in  mass  from  one  side  to  the 
other,  but  each  chord  sends  off  four  or  five  fasciculi,  which  are 
interwoven  with  their  congeners,  like  the  fingers  of  the  two 
hands  when  interlocked  obliquely.  It  is  to  be  observed  that 
the  whole  mass  of  the  anterior  chords  is  not  subjected  to  such 
distribution;  for  the  fasciculi  just  described  come  from  their  an- 
terior and  from  their  posterior  faces,  while  the  intermediate 
part  is  permitted  to  pursue  its  course  straight  upwards.  This 
decussation,  upon  which  so  much  interesting  physiological  spe- 
culation depends,  though  known  for  the  last  century,  and  spoken 
of  by  Mistichelli  and  Petit,  has  been  strangely  overlooked  by 
many  anatomists,  and  is  even  positively  denied  by  some.  There 

*  Rechercbes  sur  le  Syst.  Nerv,  et  sur  celui  du  Cerveau.   Paris,  1809. 


SPINAL  MARROW.  329 

are  other  places  where  the  fasciculi  of  the  spinal  marrow  seem 
to  cross  from  one  side  to  the  other,  but  the  fact  is  not  yet  veri- 
fied sufficiently. 

The  existence  of  canals  in  the  spinal  marrow  has  been  from 
time  to  time  announced  ;*  though  authors  differ  much  in  the  ac- 
counts of  their  position  and  extent.  When  such  an  appearance 
is  presented,  it  is  supposed,  by  some,  to  be  either  the  result  of 
disease  or  of  accident,  with  the  exception  of  a  small  one  of  eight 
or  nine  lines  long,  which  communicates  at  one  end  with  the 
fourth  ventricle,  and  is  shut  up  at  the  other,  f 

The  Spinal  Marrow  sends  out  from  its  sides  thirty  pairs  of 
nerves,  which,  like  the  vertebrae,  are  arranged  into  cervical,  dor- 
sal or  thoracic,  lumbar,  and  sacral.  Of  these  there  are  eight 
cervical,  one  of  which,  from  its  escaping  between  the  occiput 
and  the  first  vertebra,  is  most  usually  designated  as  sub-occipital, 
and,  therefore,  the  number  of  the  cervical  nerves  is  reduced  to 
the  same  with  that  of  the  vertebras,  to  wit,  seven.  There  are 
twelve  pairs  of  dorsal  nerves,  five  of  lumbar,  and  five  of  sacral. 
Occasionally,  there  is  a  sixth  sacral  nerve  on  each  side,  which 
augments  the  number  of  spinal  nerves  to  thirty-one  pairs. 

Every  spinal  nerve  is  formed  from  two  roots  on  the  same 
level,  one  before  and  the  other  behind,  and  each  root  consists  in 
several  fasciculi  of  nervous  matter.  The  front  root  arises  from 
the  anterior  chord  of  the  medulla  spinalis,  and  the  other  from 
the  posterior  chord.  The  posterior  root  is  larger  than  the  ante- 
rior, but  has  fewer  fasciculi  in  its  composition,  and  is  not  so  fila- 
mentous. The  two  roots  are  kept  asunder  by  the  Ligamentum 
Denticulatum.  The  fasciculi  of  each  are  slightly  connected  by 
a  loose  delicate  cellular  substance,  and  as  they  are  about  pene- 
trating the  dura  mater,  each  fasciculus  collects  into  a  single 
chord,  which  passes  the  dura  mater  through  its  appropriate  fo- 
ramen. In  this  way  the  anterior  and  posterior  roots  are  kept 
distinct  till  they  have  got  to  the  outside  of  the  membrane  men- 
tioned; but  the  foramina,  through  which  they  pass,  border  close- 
ly upon  one  another.  The  posterior  root,  then  forms  a  ganglion 

*  Gall,  Portal,  Morgagni. 

f  Meckel,  p.  605,  vol.  ii.  Bichat,  vol.  Hi.  p.  128. 


330  NT3RVOITS  SYSTEM. 

of  a  round  or  oval  shape;  from  whose  external  extremity  there 
proceeds  a  single  nervous  trunk,  which  is  joined  immediately  at 
its  commencement  by  the  anterior  root. 

With  the  exception  of  the  ganglions  of  the  sacrum,  which 
are  in  the  spinal  cavity  of  that  bone,  these  bodies  are  placed  in 
the  intervertebral  foramina.  The  size  of  the  ganglion  is  not 
proportionate  to  that  of  the  nerve  from  which  it  proceeds;  for 
some  of  the  dorsal  ganglions  are  the  largest,  while  those  of  the 
sacrum  are  smaller  than  any  others. 

The  two  nerves  of  the  same  pair,  though  generally  symme- 
trical, or  precisely  resembling,  are  not  invariably  so ;  sometimes 
one  is  placed  higher  than  another,  and  the  number  of  the  fasci- 
culi may  be  greater  or  smaller.  The  roots  of  the  nerves  are 
much  nearer,  or  cluster  more  at  the  extremities  of  the  spinal 
marrow,  than  in  its  middle.  The  lumbar  and  sacral  nerves  are, 
indeed,  so  close  together  and  so  much  in  a  bunch,  that  the  ar- 
rangement is  designated  by  the  term  Cauda  Equina. 

The  Cervical  Pairs  of  Nerves  are  nearly  horizontal  in  their 
course  from  the  medulla  spinalis  to  the  foramina  in  the  dura 
mater.  The  first  one,  of  the  sub-occipital,  is  strictly  so ;  the 
others  incline  very  gradually  more  and  more  downwards.  They 
have,  therefore,  but  a  very  short  passage  before  they  reach  the 
intervertebral  foramina.  Their  roots  are  so  pyramidal,  that  the 
bases  nearly  touch  each  other,  and,  for  the  most  part,  are  con- 
nected by  an  anastomosing  filament,  which  goes  from  the  upper 
margin  of  the  root  below  to  the  lower  margin  of  the  root  above. 
These  anastomoses  are  found  connecting  the  upper  with  the 
lower  fasciculi,  both  on  the  anterior  and  posterior  chords  of  the 
medulla,  but  more  uniformly  as  regards  the  latter.  Modifica- 
tions of  this  arrangement,  which  it  is  unnecessary  to  specify, 
are  met  with  in  different  subjects. 

The  Dorsal,  or  Thoracic  Pairs,  are  much  inferior  in  size  to 
any  other  nerves,  except  the  inferior  sacral.  Anastomosing 
filaments  do  not  generally  prevail,  yet  they  are  found  occasion- 
ally, as  in  the  neck,  upon  the  two  or  three  upper  pairs.  The 
first  one  has  the  broad  pyramidal  or  triangular  root  of  a  cervi- 


MEMBRANES  OF  THE  SPINAL   MARROW.  331 

cal  nerve,  and  resembles  it  also  in  volume.  The  second  is  the 
smallest  of  any;  they  then  go  on  increasing  in  size  to  the  low- 
est, but  not  in  an  uniform  gradation.  They  are  successively 
more  oblique,  and  consequently  longer  from  their  bases  to  their 
passage  through  the  dura  mater. 

The  Lumbar  and  the  Sacral  Pairs  arise  closely  upon  each 
other,  indeed  in  absolute  contact  successively,  from  the  lower 
end  of  the  medulla  spinalis.  As  their  place  of  origin  is  within 
the  precincts  of  the  first  lumbar  vertebra  and  the  two  or  three 
last  dorsal,  they  all  observe  a  very  oblique  course  in  their  de- 
scent to  the  vertebral  foramina,  and  the  lower  ones  are  almost 
vertical.  Notwithstanding  they  are  in  contact,  and  adhere  by 
a  loose  cellular  substance,  yet  there  are  no  anastomosing  fila- 
ments between  the  adjacent  roots.  From  the  sacral  gangli- 
ons presenting  the  peculiarity  of  being  situated  in  the  spinal 
cavity  of  the  sacrum,  instead  of  in  the  foramina,  the  single  nerve 
formed  from  the  ganglion  and  the  anterior  fasciculus,  has  to 
proceed  a  distance  more  or  less  considerable  in  the  spinal  cavi- 
ty before  it  can  escape  from  it. 

SECT.  II. MEMBRANES  OF  THE  SPINAL  MARROW. 

Of  the,  Dura  Mater  of  the  Medulla  Spinalis. 

This  membrane,  forming  the  exterior  envelope  of  the  spinal 
marrow,  extends  from  one  end  of  the  spinal  canal  to  the  other, 
being  continuous  above  with  the  dura  mater  of  the  brain,  and 
terminating  below  in  a  cul-de-sac,  or  closed  extremity.  It  does 
not  adhere  to  the  surface  of  the  spinal  canal,  but  lies  loosely  at- 
tached to  it,  with  the  exception  of  the  first  cervical  vertebra,  to 
which  it  is  closely  fastened.  Between  it,  and  the  ligaments  and 
periosteum  on  this  surface  of  the  bones  of  the  spine,  is  a  long, 
loose,  and  spare  cellular  substance,  generally  somewhat  watery, 
and  containing  in  the  lumbar  and  sacral  regions,  a  reddish  adi- 
pose matter. 

This  membrane  is  so  much  larger  than  the  medulla,  that  it 
invests  it  very  loosely  and  always  presents  a  collapsed  appear- 
ance. Where  the  nerves  penetrate,  it  furnishes  to  each  one,  a 


332  NERVOUS  SYSTEM* 

sheath  as  far  as  the  inter  vertebral  foramen.  Those  sheaths  are 
longer  for  the  cauda  equina  than  elsewhere,  and,  of  course,  ob- 
serve the  same  successive  obliquity  with  the  nerves  to  which 
they  belong.  Having  reached  the  intervertebral  foramina,  they 
enlarge  so  as  to  enclose  the  ganglions,  adhere  by  cellular  sub- 
stance to  the  contiguous  periosteum,  and  are  then  insensibly 
lost  in  the  tunics  of  the  nervous  trunks.  The  internal  surface 
of  the  dura  mater  is  smooth  and  shining,  which  is  probably 
owing  to  the  tunica  arachnoidea  being  reflected  over  it.  This 
membrane  has  a  fibrous  texture,  and,  with  inconsiderable  ex- 
ceptions, is  like  that  of  the  brain. 

Of  the.  Tunica  Arachnoidea  of  the  Medulla  Spinalis. 

This  membrane  is  next  to  the  dura  mater,  and  is  easily  dis- 
tinguished by  its  extreme  delicacy,  thinness,  and  almost  perfect 
transparency.  It  is  destitute  of  red  blood  vessels.  It  forms, 
also,  a  complete  envelope  for  the  medulla  spinalis,  and  adheres 
to  it  only  very  loosely  by  means  of  long,  slender,  and  scattered 
filaments  of  cellular  substance.  If  the  dura  mater  be  slit  up  its 
whole  length  before  and  behind,  and  a  blow-pipe  be  introduced 
at  one  end  of  the  medulla,  between  the  pia  mater  and  the  arach- 
noidea; inflation  will  cause  the  latter  to  rise,  and  to  present 
itself  as  a  long  capacious  tube,  detaching  on  each  side  processes- 
which  surround  the  roots  of  the  nerves.  These  processes  having 
reached  the  points  where  the  nerves  penetrate  the  dura  mater, 
are  then  reflected  upon  its  internal  face,  and  are  supposed  to 
give  it  the  glistening  appearance.  The  processes  enclosing  the 
fasciculi  of  the  spinal  nerves,  are  particularly  conspicuous  about 
the  Cauda  Equina. 

Of  the  Pia  Mater  of  the  Medulla  Spinalis. 

This  third  envelope  of  the  spinal  marrow  forms  also  a  com- 
plete investment  of  the  latter,  and  adheres  very  closely  to  it. 
Its  external  face  is  smooth,  and  is  in  contact  with  the  arachnoi- 
dea, from  which  it  may  be  readily  separated  by  inflating  the 
latter.  But  from  the  middle  of  its  internal  face  both  anteriorly 
and  posteriorly,  a  process  or  partition  penetrates  into  the  middle 


MEMBRANES  OF  THE  SPINAL  MARROW.  333 

fissures  of  the  medulla  spinal  is,  and  reaches  to  their  bottoms. 
From  these  partitions  there  propeed  a  great  number  of  small 
vascular  canals,  that  pass  in  various  directions  through  the  me- 
dulla, and  anastomose  freely  with  each  other.  This  arrangement 
is  rendered  sufficiently  obvious  by  injecting  and  then  destroying 
the  medulla  in  an  alkaline  solution;  or  if  the  medulla  be  hardened 
by  neutral  salts  or  acids,  it  splits  into  longitudinal  radiated  la- 
minae, divisible  into  chords,  whereby  the  arrangement  is  made 
equally  manifest.  A  fact  of  some  consequence  is  thus  estab- 
lished, to  wit,  the  similitude  between  the  structure  of  a  nerve 
and  of  the  medulla  spinalis. 

At  the  inferior  end  of  the  medulla  the  pia  mater  becomes  a 
single  chord,  which  is  continued  among  the  cluster  of  nerves 
to  the  lower  end  of  the  tube  formed  by  the  dura  mater,  and 
there  it  joins  with  the  latter.  •  As  a  membrane,  the  pia  mater  is 
much  more  complete  than  the  corresponding  one  of  the  brain, 
has  more  strength,  but  is  not  so  vascular.  Its  thickness  in- 
creases in  its  descent.  It  is  of  a  yellowish-white  colour.  It 
seems  to  hold  the  medulla  somewhat  in  a  state  of  compression, 
for  when  a  puncture  is  made  through  it,  the  medullary  substance 
protrudes  like  a  hernia.  It.  goes  from  the  medulla  to  the  fasci- 
culi of  nerves  and  forms  their  neurileme  or  sheath. 

Of  the  Ligamenta  Denticula. 

These  bodies  are  narrow  semi-transparent  bands,  and  very 
thin,  which  are  placed  one  on  either  side  of  the  medulla  spina- 
lis, between  the  pia  mater  and  the  tunica  arachnoidea.  They 
commence  at  the  occipital  foramen,  and  descending  between 
the  anterior  and  the  posterior  fasciculi  of  nerves,  terminate 
somewhat  above  the  inferior  extremity  of  the  medulla. 

Each  one  is,  at  its  commencement,  in  front  of  the  accessory 
nerve,  and  in  descending  is  rather  nearer  to  the  posterior  than 
to  the  anterior  fasciculi.  By  its  internal  margin  it  adheres 
with  uniformity  to  the  pia  mater,  but  the  external  margin  has 
a  very  different  arrangement;  for  it  sends  off  at  intervals  from 
twelve  to  twenty-four  serrated  or  denticulated  processes,  which 
for  the  most  part  are  placed  between  the  fasciculi  of  cervical 
and  of  dorsal  nerves.  The  extremities  of  these  teeth  are  small, 
VOL.  IL— 43 


334  NERVOUS  SYSTEM. 

rounded,  and  strong,  are  surrounded  by  the  arachnoidea,  and 
adhere  very  firmly  to  the  dura  mater,  being  pointed  down- 
wards. The  position  and  connexions  of  each  ligamentum  den- 
tic  ulatum  are  such,  as  to  make  it  serve  as  a  fastening;  which  use 
is  additionally  indicated  by  its  fibrous  texture,  and  by  the  ne- 
cessity that  the  medulla  has  for  such  fastening,  in  consideration 
of  its  being  so  deficient  in  filling  up  the  vertebral  canal. 

It  is  taught  by  many  anatomists,  that  the  ligamenta  denticu- 
kta,  from  the  opposite  sides,  join  at  the  lower  end  of  the  spinal 
marrow  to  form  the  single  cylindrical  chord,  just  mentioned, 
that  passes  thence  to  the  lower  end  of  the  spinal  cavity,  and  has 
been  described  as  an  emanation  from  the  pia  mater.  I  am, 
however,  induced  to  think  with  Meckel  and  others,  that  gene- 
ral analogy  is  in  favour  of  the  latter. 

SECT.  III. OF  THE  BLOOD  VESSELS  OF  THE  MEDULLA  SPINALIS. 

The  Arteries  of  the  Spinal  Marrow  are  derived  from  the 
VertebralSj  Intercostals,  Lumbar,  and  Sacral  Arteries. 

1.  The  Posterior  Spinal  Artery  (Jlrteria  Spinalis  Posterior) 
is  the  lowest  branch  of  the  vertebral,  given  off  in  the  cavity  of 
the  cranium.     It  reaches,  soon  after  its  origin,  the  posterior  face 
of  the  Medulla  Spinalis,  and  runs  to  the  lower  extremity  of  the 
latter,  on  the  side  of  its  posterior  fissure.     Its  course  is  parallel 
with  its  fellow,  and  very  serpentine.     In  its  descent  it  is  con- 
tinually re-enforced  by  the  small  branches  which  get  into  the 
spinal  cavity  through  each  of  the  intervertebral  foramina. 

2.  The  Anterior  Spinal  Artery  (jlrleria  Spinalis  interior) 
arises  above  the  last  from  the  vertebral.     Shortly  after  its  ori- 
gin it  unites  with  its  fellow  into  a  common  trunk,  which  de- 
scends along  the  anterior  fissure  of  the  medulla  spinalis,  but  is 
subject  to  interruptions.     It  also  is  re-enforced  by  twigs  from 
the  arteries  that  pass  into  the  spinal  cavity  through  the  inter- 
vertebral  foramina.     In  its  whole  course  it  sends  off  branches 
from  each  side  to  the  medulla  spinalis. 

The  Cauda  Equina  is  supplied  by  arteries  from  the  Lumbar 


THE  ENCEPHALON.  335 

and  from  the  Sacral  Arteries,  which  reach  it  through  the  fora- 
mina, between  the  vertebrae  and  in  the  sacrum. 

The  Veins  of  the  Spinal  Marrow  are  very  abundant.  A  large 
one,  called  the  Sinus  Columnar  Vertebralis,  is  situated  in  the 
spinal  cavity,  on  the  posterior  face  of  the  bodies  of  the  vertebrae, 
between  their  ligamentous  covering  and  the  dura  mater.  One 
of  these  veins  exists  on  each  side  of  the  middle  line.  They 
detach  a  considerable  number  of  branches,  which  run  trans- 
versely, and  anastomose  with  one  another  on  the  body  of  each 
vertebra,  so  that  each  vertebra  has  its  little  system  of  anasto- 
mosing branches,  called  Circelli  Venosi.  These  anastomoses 
communicate  with  the  intercostal  veins,  and*  indeed,  with  all 
such  as  are  on  the  outside  of  the  spinal  column,  by  means  of 
small  branches  that  get  out  by  the  intervertebral  foramina. 
They  receive  the  veins  from  the  bodies  of  the  vertebrae,  and 
from  the  dura  mater  of  the  spine. 

The  two  sinuses  may  be  traced  as  low  down  as  the  inferior 
end  of  the  sacrum,  where  they  arise  by  small  trunks  from  the 
fatty  matter  which  surrounds  the  lower  end  of  the  cauda  equina. 
When  their  size  is  somewhat  augmented  by  their  ascent,  they 
communicate  by  a  large  transverse  branch.  The  superior  end 
of  each  sinus  terminates  by  several  anastomoses  with  the  verte- 
bral vein,  and  with  the  anterior  occipital  sinus;  through  the 
latter  of  which  its  blood  is,  finally,  carried  into  the  lateral  sinus. 
For  a  farther  account,  see  Sinus  Vertebrales. 


CHAPTER  II. 

OF  THE  ENCBPHALON,  OR  BRAIN. 

BY  this  term  is  designated  that  section  of  the  central  portion 
of  the  nervous  system,  which  is  contained  within  the  bones  of 
the  cranium.  In  jts  general  configuration  it  differs  materially 
from  the  medulla  spinalis  in  being  spheroidal  or  oval.  It  is 


336  NERVOUS  SYSTEM. 

surrounded  by  the  same  membranes;  to  wit,  the  Dura  Mater, 
externally,  the  Tunica  Arachnoidea  next,  and  the  Pia  Mater, 
internally. 

The  Encephalon  is  formed  by  cineritious  and  medullary 
matter,  and,  as  a  mass,  consists  of  four  distinct  portions.  The 
Medulla  Oblongata,  which  is  a  continuation  of  the  spinal  mar- 
row, or  its  superior  part;  the  Protuberantia  Annularis,  or  Pons 
Varolii,  which  is  placed  at  the  upper  extremity  of  the  Medulla 
Oblongata;  the  Cerebrum,  which  occupies  six  or  seven-eighths 
of  the  cavity  of  the  cranium;  and  the  Cerebellum,  which  lies 
upon  the  posterior  fossae  of  the  base  of  the  cranium.  As  the 
brain  is  a  double  organ,  each  of  these  parts  is  symmetrical,  or 
consists  in  right  and  left  halves  perfectly  alike. 


SECT.  I. OP  THE  MEMBRANES  OP  THE  BRAIN,  OR  ENCEPHALON. 

Of  the  Dura  Mater. 

This  membrane,  the  most  exterior  of  the  three  belonging  to 
the  encephalon,  lines  the  whole  internal  face  of  the  cavity  of. 
the  cranium,  and  is  attached  with  great  tenacity  to  it,  particu- 
larly in  early  life,  from  which  cause  it  is  also  considered  as 
an  internal  periosteum. 

Its  external  surface  has  a  rough  and  unequal  appearance,  and 
adheres  much  more  strongly  where  the  sutures  exist  than  else- 
where, owing  to  its  detaching  many  large  filaments,  which  pe- 
netrate into  the  sutures  and  reach  to  the  pericranium.  The 
adhesion  to  the  surface  generally  of  the  bones  is  accomplished 
by  fine  filaments  of  fibres,  and  by  very  numerous  and  small 
blood  vessels  which  become  evident  from  the  dots  of  blood 
collected  upon  its  surface,  when  the  bones  are  torn  up,  as  in 
the  usual  manner  of  examining  the  head.  To  the  base  of  the 
cranium,  its  adhesion  is  still  stronger,  owing  to  the  abundance, 
of  the  foramina  and  fissures  there;  \g  the  margin  of  each  one  of 
which  it  is  fixed  with  extreme  compactness,  and  may  be  con- 
sidered as  continuous  with  the  adjacent  pericranium. 

The  external  surface  is  marked  by  the  arteries  and  veins 
which  creep  and  ramify  through  it,  and  make,  as  mentioned 
elsewhere,  corresponding  furrows  in  the  bones. 


MEMBRANES  OP  THE  BRAIN.  337 

The  Dura  Mater  consists  of  two  laminae,  one  within  the 
other;  they,  however,  are  attached  so  closely  in  the  greater  part 
of  their  extent,  that  it  requires  the  knife,  or  strong  artificial 
force,  to  separate  them.  Sometimes,  in  tearing  off  the  skull- 
cap of  a  middle-aged  person,  the  external  lamina  is  brought 
away  with  the  bone. 

Several  processes  arise  by  a  duplicature  of  the  internal  la- 
mina of  the  dura  mater,  and  extend  from  the  circumference  to- 
wards the  centre  of  the  cavity  of  the  cranium.  They  are  as 
follow: — 

The  Falx  Cerebri  separates  the  hemispheres  of  the  brain,  and 
is,  consequently,  precisely  under  the  middle  line  of  the  head. 
Its  shape  is  well  indicated  by  its  name.  It  commences  by  a 
small  point  from  the  middle  of  the  body  of  the  sphenoid  bone, 
and  continues  to  arise  along  the  crista  galli,  the  spine,  and 
middle  line  of  the  frontal  bone,  the  sagittal  suture  and  the  up- 
per limb  of  the  occipital  cross,  till  it  reaches  the  internal  occi- 
pital protuberance.  It  is  about  an  inch  broad  in  front,  where 
it  begins,  but  it  increases  continually,  though  gradually,  in 
breadth  till  its  termination,  where  it  is  two  or  two  and  a  half 
inches  wide.  It  is  strongly  fastened  along  the  crista  galli,  and 
*-at  the  foramen  coecum,  and  being  also  fastened  behind  to  the 
tentorium,  (with  which  it  is  continuous,)  as  well  as  along  the 
intermediate  points  of  bone,  it  is  kejit  in  a  state  of  strict  tension, 
which  does  not  admit  of  its  wavering  to  one  side  or  to  the  other. 
Its  inferior  margin  is  very  concave,  and  goes  to  within  a  small 
distance  of  the  corpus  callosum.  There  are  sometimes  conside- 
rable apertures  in  it,  through  which  the  flat  surfaces  of  the  he- 
mispheres come  in  contact. 

The  Tentorium  Cerebelli,  another  process  of  the  dura  mater, 
is  placed  transversely  across  the  posterior  part  of  the  cranium, 
and  separates  the  cerebellum  from  the  posterior  lobes  of  the 
cerebrum.  It  is  continuous  with  the  posterior  end  of  the  falx 
major,  whereby  these  two  processes  exercise  a  mutual  tension. 
The  tentorium  is,  therefore,  kept  convex  above  and  concave 
below. 


338  NERVOUS  SYSTEM. 

Its  form  is  crescentic;  its  outer  circumference  is  extended 
along  the  horizontal  limbs  of  the  occipital  cross,  and  along  the 
superior  corner  or  margin  of  the  petrous  bones  to  the  posterior 
clinoid  process.  The  internal  circumference  is  much  smaller 
and  unattached,  and  being  placed  immediately  behind  the  sella 
turcica,  it  leaves  an  opening  (the  Foramen  Ovale)  which  is  near- 
ly of  the  same  size  with,  and  occupied  by  the  tuber  annulare, 
and  the  crura  cerebri.  The  anterior  extremities  of  the  crescent 
are  continued  from  the  posterior  clinoid  process  to  the  anterior 
on  each  side,  so  that  a  deep  depression  is  formed  for  lodging 
the  pituitary  gland. 

The  Falx  Cerebelli  is  a  small  triangular  process  of  the  dura 
mater,  which  extends  in  the  middle  line  from  the  under  surface 
of  the  tentorium  to  the  posterior  margin  of  the  occipital  fora- 
men. Its  base  is  above,  and  its  point  below:  the  latter  termi- 
nates by  a  small  bifurcation.  It  adheres  by  its  posterior  mar- 
gin to  the  middle  inferior  limb  of  the  occipital  cross;  the  ante- 
rior margin  is  free,  and  serves  to  separate  the  two  hemispheres 
of  the  cerebellum." 

The  Dura  Mater  is  essentially  fibrous,  as  is  sufficiently  evi- 
dent at  whatever  point  it  may  be  examined.  These  fibres  have 
no  settled  course,  but  cross  each  other  in  every  direction.  It 
is  white,  sufficiently  transparent  for  the  vessels  of  the  pia  ma- 
ter to  be  imperfectly  seen  through  it,  and  almost  inelastic.  Its 
internal  face  is  smooth  and  polished,  and  is  covered  or  lined  by 
the  tunica  arachnoidea,  the  halitus  from  which  gives  it  a  slip- 
pery feel.  It  is  insensible  to  common  excitants,  such  as  cutting, 
or  even  cauterizing  it;  from  which  circumstance,  together  with 
the  common  inability  of  anatomists  to  trace  nerves  into  its  struc- 
ture, it  is  supposed,  by  many,  to  be  entirely  destitute  of  them. 
The  venerable  Chaussier,  however,  takes  a  different  position  in 
regard  to  these  points,  and  says,  that  it  has  sensibility,  and  that 
though  none  of  the  cerebral  nerves  can  be  traced  into  it,  yet, 
by  attentive  examination,  it  is  found,  that  filaments  from  the 
sympathetic  nerve  follow  the  ramifications  of  its  middle  or  great 
artery.* 

*  Exposition  de  L'Encephale,  p.  29. 


MEMBRANES  OF  THE  BRAIN.  339 

It  is  well  supplied  with  blood  vessels,  both  arteries  and  veins. 
The  former  are  derived  principally  from  the  branches  of  the  in- 
ternal maxillary  of  either  side,  which  get  into  the  cranium 
through  the  foramen  spinale  and  ovale.  There  are  branches 
also  from  the  aethmoidal,  the  inferior  pharyngeal,  and  the  ver- 
tebral. The  branch  of  the  internal  maxillary  called  meningea 
magna,  divides  into  two,  of  which  the  anterior  being  the  more 
considerable,  gains  the  anterior  and  inferior  angle  of  the  parie- 
tal bone;  but  the  other  is  directed  backwards  to  the  squamous 
portion  of  the  temporal.  Each  of  these  branches  is  subdivided 
into  a  considerable  number  of  smaller  ones,  which  for  the  most 
part  incline  backwards.  Their  capillary  terminations  are  sup- 
posed by  Bichat  to  be  in  small  number  comparatively,  and  to  be 
limited  principally  to  those  of  nutrition. 

Some  of  the  veins  accompany  the  arteries,  as  in  other  parts 
of  the  body,  and  empty  into  the  sinuses  about  the  base  of  the 
cranium.  In  the  case  of  both  arteries  and  veins,  there  is,  how- 
ever, a  very  considerable  anastomosis  with  the  blood  vessels  of 
the  diploic  structure  of  the  cranium,  and  with  those  of  the  in- 
teguments. 

Of  the  Sinuses  of  the  Dura  Mater. — The  sinuses  are  large 
cavities  placed  between  the  two  laminae  of  the  dura  mater,  and 
receive  the  blood  from  the  veins  of  the  pia  mater.  They  are 
formed  by  the  separation  of  these  laminae,  and  are  'lined  by  a 
membrane  corresponding  with  the  internal  coat  of  the  veins. 

-1.  The  Sinus  Longitudinalis  Superior  extends  along  the  whole 
base  of  the  falx  cerebri,  from  the  ethmoid  bone  to  the  tentori- 
um,  where  it  terminates  in  the  lateral  sinuses.  It  begins  at  the 
foramen  coecum  in  a  small  pointed  manner,  and,  according  to 
some  anatomists,  by  a  small  vein,  which  passes  from  the  nose 
through  this  foramen;  it  is  successively  increased  in  size  frorni 
before  backwards,  and  is  of  a  prismatic  shape.  One  side  of  the 
prism  is  upwards,  and,  of  course,  is  formed  by  the  external  la- 
mina of  the  dura  mater;  while  the  other  two  parietes  are  late- 
ral, and  are  formed  by  the  duplicature  of  the  internal  lamina. 
Its  cavity  presents.a  number  of  small  cords,  round  or  flattened, 


340  NERVOUS  SYSTEM. 

passing  from  one  side  to  the  other;  they  are  called  Chordae  Wil- 
lisii  or  Trabeculae,  and  prevail  principally  at  its  back  part. 

The  longitudinal  sinus  receives  on  each  side  from  ten  to  twelve 
large  veins,  which  bring  the  blood  from  the  pia  mater.  Those 
from  the  convex  surface  of  the  brain  are  joined  just  before  enter- 
ing the  sinus  by  such  as  belong  to  the  flat  side  of  the  hemispheres. 
These  veins  enter  the  sinus,  for  the  most  part,  obliquely  forwards, 
or  in  a  manner  opposed  to  its  circulation.  The  most  posterior 
ones  previously  glide  eight  or  ten  lines  between  the  laminae  of 
the  dura  mater,  and  are.  somewhat  tortuous;  they  are  also 
furnished  with  valves,  which  circumstance,  besides  their  oblique 
entrance  into  the  sinus,  is  a  provision  against  their  being  filled  by 
the  regurgitating  blood.  This  sinus  also  receives  several  veins 
from  the  bones,  and  some  from  the  scalp,  which  traverse  the 
bones  at  different  places :  among  the  largest  of  them  are  those 
that  come  through  the  parietal  foramina.  The  dura  mater  itself 
sends  some  of  its  veins  into  this  sinus. 

In  the  longitudinal  sinus,  towards  its  posterior  part,  are  found 
a  considerable  but  variable  number  of  small  granular  bodies; 
some  in  clusters,  others  insulated;  and  from  the  size  of  a  pin's 
head  to  a  line  or  more  in  diameter.  They  are  the  Glandular 
Pacchioni;  they  have  no  excretory  ducts  that  have  been  dis- 
covered, and  it  is  entirely  uncertain  whether  any  specific  fluid 
is  secreted  from  them.  These  bodies  are  also  to  be  found  on 
the  surface  of  the  dura  mater  near  this  sinus ;  some  of  them,  in- 
deed, make  foramina  through  the  dura  mater,  and  corresponding 
depressions  in  the  skull.  One  on  each  side,  larger  than  usual, 
and  near  the  parietal  foramen,  is  remarkable  for  this. 

2.  The  Sinus  Laterales,  one  on  each  side,  are  situated  in  the 
base  of  the  tentorium,  and  follow  its  course  along  the  grooves  of 
the  occipital  and  parietal  bones.  They  then  leave  the  tentorium 
and  go  along  the  groove  in  the  mastoid  portion  of  the  temporal 
bone  to  reach  the  posterior  foramen  lacerum,  where  they  ter- 
minate in  the  internal  jugular  veins.  Their  shape  is  ovoidal, 
instead  of  prismatic,  as  the  longitudinal  sinus  is;  they  are  also 
larger  than  it. 

The  sinus  of  the  right  side  is  very  frequently  larger  than  that 
of  the  left,  and  seems  to  be  more  a  continuation  of  the  superior 


MEMBRANES  OF   THE  BRAIN.  34 1 


longitudinal  sinus.  In  some  rare  cases  one  of  these  sinuses  is 
deficient.  The  lateral  and  inferior  veins  of  the  cerebrum,  and 
the  inferior  veins  of  the  cerebellum  run  into  the  lateral  sinuses. 

3.  The  Sinus  Longitudinalis  Inferior  is  situated  in  the  falx 
cerebri  just  above  its  concave  edge.     It  is  much  smaller  than 
the  superior,  and  terminates  behind  in  the  sinus  quartus.     It  re- 
ceives the  veins  of  the  falx,  and  sometimes  a  few  from  the  cor- 
responding parts  of  the  hemispheres. 

4.  The  Sinus  Quartus,  or  Rectus,  is  situated  in  the  tentorium, 
where  the  latter  is  joined  by  the  falx  major  or  cerebri.     It  is 
triangular  or  prismatic,  and  runs  from  the  anterior  margin  of 
the  tentorium  to  the  posterior,  where  it  terminates  in  the  extre- 
mity of  the  longitudinal  sinus.     The  general  union  which  is  there 
found  between  the  longitudinal,  the  fourth,  and  the  lateral  sinuses, 
constitutes  the  Torcular  Hierophili. 

The  anterior  extremity  of  the  fourth  sinus,  besides  receiving 
the  inferior  longitudinal,  is  joined  by  the  Vena  Galeni,  a  single 
trunk,  formed  by  the  junction  of  the  two  veins  of  the  middle  of 
the  velum  interpositum,  and  extending  from  the  posterior  margin 
of  the  fornix  to  the  beginning  of  the  fourth  sinus.  The  latter,  in 
its  course,  also  receives  the  superior  veins  of  the  cerebellum, 
with  the  exception  of  the  most  anterior  ones,  which  terminate  in 
the  Vena  Galeni. 

5.  The  Sinus  Petrosi  are  small  cylindrical  cavities,  and  are 
so  called  from  being  situated  on  the  petrous  bone.     There  are 
two  on  each  side ;  one  above  and  the  other  below.     The  former 
is  the  Superior,  and  runs  from  the  cavernous  sinus  along  the  su- 
perior margin  of  the  petrous  bone  to  join  the  lateral  sinus,  where 
the  latter  quits  the  tentorium  to  descend  towards  the  base  of 
the  cranium.     The  other  Petrous  Sinus  is  the  Inferior.     It  is 
larger  than  the  superior,  and  arises,  also,  from  the  cavernous 
sinus  by  its  posterior  margin.     It  then  runs  along  the  fissure  be- 
tween the  occipital  and  the  petrous  bone,  leaving  its  mark  on 
the  margin  of  these  bones,  but  principally  on  the  former,  and 
then  terminates  in  the  lateral  sinus  just  above  the  posterior  fora- 
men lacerum. 

VOL.  II.— 44 


NERVOUS  SYSTEM. 

6.  The  Sinus  Cavcrnosi,  one  on  each  side,  are  also  formed  by 
a  separation  of  the  two  laminae  of  the  dura  mater,  though  their 
'shape  is  so  different  from  that  of  the  others.     They  are  situated 
at  the  sides  of  the  sella  turcica,  and  on  the  body  of  the  sphenoid 
bone.     Their  cavity  is  very  irregular,  and  is  furnished  with  a 
number  of  filaments,  which  cross  in  every  direction,  and  give  it 
a  cellular  arrangement.     Hie  internal  carotid  artery  and  the 
sixth  nerve  traverse  it,  but  are  protected  by  its  lining  membrane 
being  reflected  over  them. 

The  cavernous  sinus  anastomoses  in  front  with  the  circular 
•sinus,  and  behind  with  the  two  petrous  sinuses  and  the  anterior 
-occipital.  It  receives,  in  front,  the  ophthalmic  veins ;  froma  bove, 
the  anterior  and  inferior  cerebral  veins;  and  on  the  sides,  some 
veins  from  the  dura  mater. 

7.  The  Sinus  Circularis  is  placed  in  the  sella  turcica,  and  sur- 
rounds the  pituitary  gland.     It  is  a  small  cavity  which  receives 
the  veins  of  this  gland,  and,  ^as  just  mentioned,  communicates 
with  the  cavernous  sinus. 

8.  In  the  posterior  part  of  the  base  of  the  cranium,  there  are 
also  some  other  sinuses,  called,  from  their  position,  Occipital. 
One  of  these  is  upon  the  basilar  process  of  the  os  occipitis,  and 
extends  itself  directly  across  the  bone,  from  the  hind  part  of  one 
cavernous  sinus  to  the  corresponding  point  of  the  other ;  and  is, 
therefore,  a  means  of  communication  between  these  two  cavities. 
Another  of  these  sinuses  extends  from  the  region  of  the  torcular 
hierophili,  or  the  upper  extremity  of  the  lateral  sinuses,  along 
the  base  of  the  falx  cerebelli,  to  the  posterior  margin  of  the  oc- 
cipital foramen,  where  it  bifurcates,  and  then  goes  along  the 
margin  of  this  foramen  to  discharge  itself  into  the  lateral  sinus 
•at  the  posterior  foramen  lacerum. 

The  smaller  sinuses  about  the  base  of  the  cranium,  besides 
the  outlets  mentioned,  have  collateral  ones,  which  pass  at  dif- 
ferent places  through  the  base  of  the  cranium,  and  run  into  the 
branches  of  the  internal  jugular  vein.  These  communications, 
as  mentioned  in  the  account  of  the  veins,  were  known  to  San- 
torini,  and  are  called  his  Emissaries. 


MEMBRANES  OF  THE  BRAIN*  343 


Of  the  Tunica  AracJmoidca. 

This  membrane  is  the  second  of  the  envelopes  of  the  brain,  and 
is  spread  over  the  surface  of  the  pia  mater,  adhering  to  it  close- 
ly in  the  greater  part  of  its  extent.  It  is  so  diaphanous  and  thin 
as  its  name  implies,  that  it  is  distinguished  with  some  difficulty, 
wherever  it  adheres  to  the  pia  mater;  which  it  does  all  over, 
with  the  exception  of  some  few  places  on  the  basis  of  the  brain, 
as,  for  example,  just  in  front  of  the  tuber  annulare,  and  behind 
the  medulla  oblongata.  There  this  membrane  may  be  seen 
stretched  from  one  prominence  to  another,  and  separated  con- 
siderably from  the  pia  mater.  It  does  not  follow  the  anfrac- 
tuosities  of  the  brain,  but  goes  directly  across  them,  from  the 
ridge  of  one  convolution  to  that  of  the  adjacent,  so  that  it  is  en- 
tirely smooth  and  uniform  in  its  distribution.  Notwithstanding 
the  general  closeness  of  its  connexion  with  the  pia  mater,  it 
may  yet  be  separated  from  it  by  careful  dissection,  by  slight 
maceration,  or  by  the  use  of  the  blow-pipe;  dropsical  effusions 
frequently  make  out  the  distinction  between  the  two  membranes ; 
also  the  deposite  of  coagulating  lymph. 

Considering  this  membrane  as  a  single  layer,  we  have  to 
speak  of  the  dura  mater,  as  lying  loosely  upon  it.  But  the  au- 
thority of  Bichat,  sanctioned  by  the  testimony  of  many  other 
anatomists,  has  assigned  to  it  a  much  more  considerable  extent. 
For  it  seems  to  be  well  ascertained,  both  by  analogy  and  by  ob- 
servation, that  it  is  a  sac;  which,  besides  covering  the  external 
surface  of  the  pia  mater,  is  reflected  over  the  internal  surface 
of  the  dura  mater,  and  gives  to  the  latter  its  smooth  shining 
appearance.  This  lining  is  on  the  same  principle  that  the  se- 
rous lamina  of  the  pericardium  lines  its  fibrous  lamina,  or  that 
the  synovial  membrane  lines  the  ligamentous  attachments  of 
an  articulation.  In  the  early  periods  of  life,  it  may  be  sepa- 
rated from  the  dura?  mater,  by  dissection.  Vicq.  D'Azyr  has 
related  a  case  in  which  it  was  detached  by  a  collection  of  pus. 
Its  places  of  reflection  to  the  dura  mater  are  on  the  basis  of  the 
cranium,  where  the  blood  vessels  and  nerves  pass  into  the 
sheaths  formed  by'the  dura  mater,  and  along  the  blood  vessels 


344  NERVOUS  SYSTEM, 

entering  into  the  sinuses.  This  membrane  is  continuous  with 
the  tunica  arachnoidea  of  the  medulla  spinalis. 

The  tunica  arachnoidea  passes  into  the  ventricles  of  the  brain 
by  the  same  apertures  that  the  pia  mater  does,  but  it  is  much 
less  manifest  there  than  elsewhere. 

The  texture  of  this  membrane  is  exceedingly  delicate  and 
fine.  It  is  always  found,  in  health,  in  a  transparent  state,  and 
is  furnished  with  neither  red  blood  vessels  nor  nerves.  It  se- 
cretes a  sort  of  halitus,  or  synovia,  which  facilitates  the  motions 
of  the  brain,  and  prevents  it  from  adhering.  Occasionally, 
this  secretion  is  so  much  augmented  as  to  constitute  a  genuine 
dropsy. 

Of  the,  Pia  Mater, 

The  Pia  Mater,  or  Tunica  Cerebri  Vasculosa,  is  in  contact 
with  the  substance  of  the  brain.  It  also  is  extremely  delicate, 
but,  unlike  the  last,  is  furnished  with  an  immense  number  of 
blood  vessels  which  go  to  or  return  from  the  brain,  and  are, 
in  most  subjects,  so  abundant  that  they  give  a  florid  appearance, 
at  a  little  distance,  to  the  whole  membrane.  Its  external  face 
appears  entirely  smooth,  owing  to  its  being  covered,  and  its 
processes  cemented  together  by  the  tunica  arachnoidea;  but  its 
internal  face  exhibits  these  processes  as  following  precisely 
the  anfractuosities  of  the  brain;  consequently,  it  is  very  un- 
equal. 

The  pia  mater  presents,  along  the  course  of  the  longitudinal 
sinus,  an  abundance  of  those  small  graniform  bodies,  existing 
also  in  this  sinus,  and  called  Glandulae  Pacchioni.  They  beset 
the  veins  as  they  enter  into  the  longitudinal  sinus,  and  even 
follow  them  there,  so  that  there  is  a  chain  of  them  from  the 
surface  of  the  pia  mater,  into  the  sinus.  They  are  frequently 
so  abundant  an  the  superior  part  of  the  hemispheres,  near  the 
great  fissure,  that  they  cause  the  dura  and  pia  mater  to  adhere, 
as  if  from  inflammation.  It  is  the  larger  of  this  kind  which 
frequently  produce  an  absorption  of  the  dura  mater,  and  of  the 
internal  table  of  the  skull.  These  bodies  are  also  found,  along 
with  the  pia  mater,  in  the  ventricles  of  the  brain,  as  at  the  ex- 


MEMBRANES  OP  THE  BRAIN.  345 

ternal  margin  of  the  plexus  choroides,  around  the  pineal  gland, 
and  at  the  bottom  of  the  fourth  ventricle. 

The  Glandule  Pacchioni,  wherever  found,  present  a  similar 
appearance  and  structure,  varying,  much  in  size:  they  are  ge- 
nerally in  clusters,  which  repose  on  common  bases.  Anato- 
mists differ  much  in  their  opinion  concerning  them.  Bichat 
acknowledges  his  complete  ignorance  on  the  subject;  Portal 
says  that  they  are  only  congeries  of  vessels  or  of  cellular  bo- 
dies filled  with  fat.  Meckel  states,  that  as  they  are  found  es- 
pecially in  the  latter  periods  of  life,  and  never  before  birth;  as 
they  never  exist  in  very  great  abundance,  except  in  persons 
who  have  often  experienced  diseases  of  the  head;  and  are  not 
observed  in  any  animal:  that  we  are  forced  to  consider  them 
as  morbific  productions,  and  not,  as  Pacchioni  conceived,  glands 
whose  excretory  ducts  opened  into  the  ventricles  of  the  brain. 

The  Pia  Mater  covers  the  upper  surface  of  the  cerebrum  with 
such  uniformity  as  not  to  require  a  detailed  description  of  it; 
where  it  sinks  into  the  great  fissure  of  the  hemispheres,  it  ad- 
heres from  the  two  sides  just  above  the  corpus  callosum.  On  the 
basis  of  the  brain,  it  penetrates  deeply  into  the  anterior  fissure, 
or  the  Fissura  Sylvii;  is  reflected  over  the  inequalities,  but  never 
in  such  a  way  as  to  leave  them ;  and  closes  up  the  bottom  of  the 
third  and  of  the  fourth  ventricle. 

The  distribution  of  the  pia  mater,  over  the  ventricles  of  the 
brain,  is  more  complicated  than  that  over  its  periphery,  and  it 
may  be  remarked,  that  this  portion  is  called,  by  some  anato- 
mists, the  Internal  Pia  Mater;  that  its  texture  is  much  more  de- 
licate, and  net-like,  and  that  it  adheres  more  closely  to  the  sub- 
jacent parts.  Being  extended  from  the  superior  surface  of  the 
cerebellum  and  of  the  tuber  annulare,  it  enters  into  the  third 
ventricle,  under  the  posterior  margin  of  the  fornix,  by  the  large 
transverse  fissure  between  the  latter  and  the  tubercula  quadrige- 
minat  By  its  course  between  the  fornix  and  thalami,  it  consti- 
tutes the  Velum  Interpositum,  or  the  Tela  Choroidea  of  Vicq. 
D'Azyr.  The  pia  mater  is  also  introduced  into  the  inferior  cor- 
nu  of  the  lateral  ventricles  along  the  internal  margin  of  the  hip- 
pocampus major,'  at  the  side  of  the  pons  varolii;  and  into  the 
fourth  ventricle  from  its  bottom  part. 


346  NERVOUS  SYSTEM. 

The  several  plexuses  of  vessels  found  in  the  ventricles  of 
the  brain  have  for  their  basis  the  pia  mater;  which  is  there  ar- 
ranged into  a  great  number  of  folds,  some  of  them  being  lon- 
gitudinal and  others  crossed.  Their  formation,  according  to  the 
new  views  which  have  been  taken  of  the  development  and 
growth  of  the  brain,  by  Tiedemann,  depends  upon  the  internal 
membrane  of  the  brain  contracting  itself  as  it  finishes  the  depo- 
site  of  medullary  matter  called  Centrum  Ovale.  The  vessels  of 
the  plexuses  are  the  arteries,  which  are  spent  upon  the  surface 
of  the  ventricles,  and  the  veins  derived  from  the  same;  the  lat- 
ter are  much  more  numerous  than  the  first. 

Of  the,  Structure  of  the  Pia  Mater. — The  pia  mater  is  com- 
monly spoken  of  as  a  complete  membrane,  yet  its  structure  is 
different  from  that  of  membranes  generally,  inasmuch  as  it  is  a 
net-work,  the  meshes  of  which  are  formed  by  arteries  and  veins, 
and  the  interstices  filled  up  by  a  loose,  weak  cellular  substance. 
Bichat  has  very  justly  observed,  that  the  union  with  the  tunica 
arachnoidea  is  solely  on  the  part  of  this  cellular  substance; 
whereas,  the  union  with  the  cerebrum  is  confined  to  the  ves- 
sels, which  are  extremely  numerous  and  very  small  before  they 
penetrate  it,  and  appear  as  bloody  points  when  we  cut  into  the 
substance  of  the  brain.  The  principal  arterial  trunks  of  the 
pia  mater  are  at  the  basis  of  the  brain;  these  trunks  divide  into 
smaller  branches,  in  the  anfractuosities  and  fissures.  The  pri- 
mary divisions  again  divide  and  subdivide  into  tubes  not  much 
exceeding  the  size  of  the  capillary  vessels.  In  this  last  state 
they  enter  the  brain  and  may  be  seen  very  readily,  either  by  a 
fine  injection  or  by  tearing  up  the  pia  mater. 

SECT.  II. OF  THE  MEDULLA  OBLONGATA. 

According  to  the  usage  of  the  best  authorities  of  the  present 
day,  who  follow  in  the  description  of  the  central  parts  of  the 
nervous  system,  the  order  of  their  development  in  the  human 
subject,  and  also  of  their  appearance  in  animals,  I  shall  describe 
the  encephalon  from  below  upwards  instead  of  from  above  down- 
wards. The  preference  thus  shown  is,  perhaps,  principally  ser- 
viceable in  fixing  upon  the  mind  the  order  of  growth  and  ap- 


THE  MEDULLA  OBLONGATA.  347 

pearance,  which,  according  to  well  established  experiments,  are1 
exactly  in  the  order  of  importance  to  life. 

The  Medulla  Oblongata,  also  called  Bulbus  Rachidicus,  ex- 
lends  from  the  superior  margin  of  the  first  cervical  vertebra  to 
the  middle  of  the  basilar.  process  of  the  os  occipitis.*  It  becomes 
gradually  larger  as  it  ascends,  and  is  about  an  inch  in  length, 
and  eight  lines  wide  at  its  base.  It  is  by  no  means  so  cylin- 
droid  as  the  medulla  spinalis,  but  presents  several  risings  and 
depressions  on  its  surface. 

The  under  surface  of  the  Medulla  Oblongata  is  divided  lon- 
gitudinally by  the  middle  fissure,  a  continuation  of  that  on  the 
front  of  the  Medulla  Spinalis.  The  fissure  is  two  or  three  lines 
deep,  which  is  rendered  manifest  by  removing  the  pia  mater. 
The  Corpora  Pyramidalia  are  placed  one  on  either  side  of  it, 
and  are  oblong  bodies;  being  a  continuation  of  the  chords  that 
decussate  from  the  opposite  sides  of  the  spinal  marrow.  These 
bodies  occupy  the  whole  length  of  the  Medulla  Oblongata,  in- 
crease in  breadth  as  well  as  in  elevation  during  their  ascent, 
and  are,  lastly,  somewhat  constricted  or  diminished  abruptly, 
where  they  join  the  Protuberantia  Annularis  or  Cerebralis. 
Precisely  at  the  latter  point,  between  their  bases,  is  a  deep  tri- 
angular pit,  into  which  penetrates  the  pia  mater.  J.  F.  Meckel 
says,  that  they  are  united  at  their  lower  extremities  by  a  small 
transverse  medullary  Commissure  of  a  line  and  a  half  in  breadth. 
This  junction  is  above  the  decussation  of  the  chords  from  which 
the  Corpora  Pyramidalia  arise. 

The  Eminentiae  Olivares  are  two  bodies;  one  on  either  side, 
at  the  external  margin  of  the  corpus  pyramidale.  They  are  about 
seven  lines  long:  two  and  a  half  wide,  and  are  elevated  to  the 
height  of  one  line.  The  elevation  ceases  somewhat  ^hort  of  the 
annular  protuberance,  but  their  interior  structure  is  continued 
into  the  latter,  and  may  be  traced  into  the  thalamus  nervi 
optici. 

Like  the  pyramidalia,  those  bodies  are  medullary  externally; 
but  within,  there  is  a  nucleus  of  cineritious  matter,  called,  from 
the  irregularities  of  its  margin,  Corpus  Fimbriatum',  and  which 
encloses  some  medullary  matter.  The  corpus  fimbriatum  is 


348  NERVOUS 

open  at  the  inner  circumference,  and  has  the  medullary  matter 
which  it  contains,  continuous  there  with  the  substance  of  the 
corpus  pyramid  ale.  Below,  its  circumference  is  continuous 
with  the  cineritious  matter  of -the  medulla  spinalis.  In  the 
slight  depression  between  the  corpus  pyramidale  and  the  emi- 
nentia  olivaris,  are  the  roots  of  the  hypoglossal  nerve. 

The  Corpora  Restiformia,  also  one  on  either  side,  are  placed 
at  the  lateral  posterior  margins  of  the  medulla  oblongata,  just 
posterior  to  the  olivares;  and  are  readily  brought  into  view  by 
elevating  the  contiguous  parts  of  the  cerebellum.  They  are  el- 
liptical risings  of  an  inch  in  length;  their  lower  extremities  are 
in  contact,  and  project  where  they  begin  to  arise  from  the  bor- 
ders of  the  posterior  fissure  of  the  medulla  oblongata;  they  then 
diverge,  and  advance  forwards  and  upwards  to  terminate  above 
in  the  cerebellum. 

The  corpus  restiforme  is  formed  of  medullary  matter,  and  is 
a  continuation  of  the  posterior  cord  of  the  medulla  spinalis. 
From  its  superior  posterior  margin  a  thin  medullary  lamina  of 
about  three  lines  square  arises,  and  being  sustained  by  the  pia 
mater,  advances  to  meet  its  fellow,  but  does  not  absolutely  touch 
it.*  From  the  anterior  margin  of  each  corpus  restiforme  there 
departs  a  second  process  of  medullary  matter,  larger  and  more 
thick  than  the  preceding,  and  being  covered  by  the  roots  of  the 
pneumogastric  and  glosso-pharyngeal  nerves,  adheres  to  the 
plexus  Choroides  of  the  fourth  ventricle. 

The  superior  face  of  the  medulla  oblongata  is  excavated  be- 
tween the  corpora  restiformia,  in  such  a  way  as  to  present  the 
outline  of  a  writing  pen,  and  is,  therefore,  called  Calamus 
Scriptorius;  which  forms  a  considerable  part  of  the  floor  of  the 
fourth  ventricle  of  the  Brain,  or  the  sinus  rhomboideus.  The 
fissure,  in  its  middle,  corresponds  with  the  slit  of  a  pen,  the 
nib  being  downwards;  and  the  fissure  extends  from  the  poste- 
rior fissure  of  the  medulla  spinalis  the  whole  length  of  the  me- 
dulla oblongata. 

The  calamus  scriptorius  is  marked  by  several  streaks  of  medul- 
lary matter,  which  extend  themselves  transversely  with  a  very 

*  Called  Pons  Sinus  Rhomboidei  by  J.  F.  Meckel. 


THE  MEDULLA  OBLONGATA.  349 

slight  degree  of  obliquity  upwards,  and  reach  the  external  mar- 
gin of  the  corpus  restiforme  of  the  corresponding  side.  These 
medullary  strias  present  some  varieties  in  regard  to  their  vo- 
lume, number,  and  arrangement  Sometimes  they  are  slightly 
elevated  narrow  lines,  which  are  perfectly  distinct  from  each 
other,  and  from  one  to  fourteen  in  number.  On  other  occa- 
sions their  volume  is  greater,  but  they  are  not  so  numerous. 
They  generally  extend,  either  one  or  all,  from  the  middle  fis- 
sure to  the  commencement  of  the  auditory  nerve,  and  are 
thereby  a  part  of  its  origin.  Sometimes  the  anterior  ones  are 
directed  towards  the  origin  of  the  trigeminus  nerve,  but  their 
union  with  it  is  not  yet  ascertained ;  the  posterior  ones  are  some- 
times blended  with  the  radical  filaments  of  the  pneumogastric 
nerve.  The  striae  themselves,  are  sometimes  interwoven  or 
blended,  and  pass  the  boundary  of  the  middle  fissure  to  join 
with  those  of  the  other  side.  Their  roots  may  be  traced  occa- 
sionally along  the  middle  fissure,  almost  to  the  front  or  under 
surface  of  the  medulla  oblongata.  Meckel,  whose  observations 
on  this  subject  are  highly  interesting,  is  disposed  to  consider 
the  stria3  not  only  as  forming  the  roots  of  the  auditory  nerve, 
but  as  also  related  closely  to  the  trigeminus  and  to  the  pneu- 
mogastric. 

On  this  surface,  also,  of  the  fourth  ventricle,  or  sinus  rhom- 
boideus,  but  in  advance  of  the  preceding  striae,  there  is  another, 
on  each  side,  still  larger,  which  may  be  distinguished  by  its  al- 
ways beginning  at  some  distance  from  the  middle  fissure.  Its 
direction  is  transverse,  and  it  passes  just  abovre  the  anterior  ex- 
tremity of  the  corpus  restiforme,  to  run  into,  or  to  assist  in 
forming,  the  root  of  the  auditory  nerve.  Its  existence  is  much 
more  constant  than  that  of  the  others.  It  is  considered  as  an 
assistant  ganglion  to  the  auditory  nerve,  and  in  cases  of  deaf- 
ness has  been  deficient.  Being  principally  cineritious,  it  is 
called  Fasciola  Cinerea.  f 

In  tracing  the  continuation  of  the  structure  of  the  medulla 
spinalis,  into  that  of  the  medulla  oblongata,  we  find  that  each 
of  the  anterior  cords  of  the  medulla  spinalis,  besides  crossing 
with  some  of  its  fasciculi  at  the  place  mentioned,  to  wit,  at  the 
decussation  of  Mistichelli,  and  continuing  its  course  upwards 

VOL.  II.— 45 


350  NERVOUS  SYSTEM. 

to  form  the  corpus  pyramidale,  sends  off  a  larger  fasciculus, 
which  ascends  behind  the  eminentia  olivaris,  and  forms  the  floor 
of  the  sinus  rhomboideus.  There  is  a  third  fasciculus  of  white 
matter  between  the  other  two,  into  which  the  anterior  column 
of  the  medulla  spinalis  is  divided.  It  is  described  by  Rosen- 
thai,  who  says,  that  it  touches  the  eminentia  olivaris,  surrounds 
it,  and,  after  having  traversed  the  annular  protuberance,  termi- 
nates in  the  tubercula  quadrigemina. 

The  posterior  cords  of  the  Spinal  marrow,  being  continued 
into  the  corpora  restiformia,  become  still  more  evidently  di- 
vided into  two  fasciculi,  from  an  increase  of  their  volume,  than 
they  were  in  the  vertebral  canal.  The  internal  of  these  fasci- 
culi stops,  by  a  pointed  termination,  near  the  borders  of  the 
sinus  rhomboideus;  while  the  external  is  continued  on  through 
the  annular  protuberance  to  the  cerebellum. 


SECT.  III. PROTUBERANTIA  ANNULARIS. 

The  Annular  Protuberance  (Protuberantia  Annular  is,  No- 
dus Cerebri,  Pons  Varolii)  is  the  large  projecting  body,  placed 
near  the  centre  of  the  base  of  the  encephalon,  at  the  top  of 
the  medulla  oblongata,  and  upon  the  junction  of  the  body  of 
the  sphenoid  bone  with  the  basilar  process  of  the  os  occipitis. 
It  is  convex,  and  about  an  inch  in  diameter,  its -transverse  mea- 
surement being  a  line  or  two  larger  than  the  other.  It  is  di- 
vided by  a  superficial  fossa  into  two  symmetrical  halves,  right 
and  left. 

When  the  pia  mater  is  removed  from  the  Protuberantia  An- 
nularis,  the  under  surface  of  the  latter  is  seen  to  be  formed  by 
transverse  medullary  fibres  which  come  from  the  crura  cere- 
belli.  When  these,  which  are  commonly  one  or  two  lines  in 
depth,  are  removed  by  scraping  or  cutting,  a  cineritious  matter 
is  exposecf,  which  is  traversed  by  numerous  layers  of  medullary 
matter,  also  going  in  a  transverse  direction.  About  two  lines 
deep  from  the  surface  of  the  protuberance,  near  the  middle  of 
each  of  its  halves,  are  found  some  longitudinal  medullary  fibres 
connected  with  cineritious  matter,  and  which  may  be  fairly 
traced  as  a  continuation  of  the  filamentous  structure  of  the  py- 


THE  CEREBELLUM.  351 

ramids.  These  fasciculi,  or  filaments,  passing  on  through  the 
protuberance,  are  continued  so  as  to  form  the  under  surface  of 
the  crura  of  the  cerehrum. 

Lying  still  deeper  than  the  medullary  fibres  alluded  to,  there 
is  an  accumulation  of  cineritious  matter,  intermixed  with  per- 
pendicular medullary  layers  situated  one  behind  the  other.  Be- 
hind (or  above  when  we  stand  erect)  this  intertexture,  a  small 
fasciculus  (the  cord  described  by  Rosenthal)  of  medullary  mat- 
ter exists,  which  is  a  continuation  of  the  intermediate  fascicu- 
lus of  the  anterior  medullary  cord  of  the  medulla  oblongata,  and 
may  be  traced  afterwards  to  the  superior  face  of  the  crus  cere- 
bri,  where  it  terminates,  as  alleged  by  Rosenthal,  in  the  Tuber- 
cula  Quadrigemina. 

SECT.  IV. OF  THE   CEREBELLUM. 

The  Cerebellum,  being  placed  in  the  posterior  fossse  of  the 
cranium,  is  separated  by  the  tentorium  from  the  posterior 
lobes  of  the  cerebrum,  beneath  which  it  lies.  It  is  connected 
with  the  Pons  Varolii  by  a  trunk  of  medullary  matter  on 
each  side,  called  the  crus  of  the  cerebellum;  which  is  a  root 
of  the  medullary  matter  entering  into  the  composition  of  the 
latter. 

It  is  of  a  rounded  form,  and  well  fitted  to  the  cavity  in  which 
it  reposes.  It  is  convex  above  and  below;  measures  about  four 
inches  in  its  transverse  diameter,  two  and  a  half  in  thickness, 
and  about  the  same  from  before  backwards.  The  upper  sur- 
face is  divided  into  two  equal  parts  or  halves,  by  a  middle 
ridge,  while  the  lower  surface  is  divided  in  the  same  way  by  a 
fossa.  These  halves  are  called  hemispheres;  their  surface  is 
marked  by  many  horizontal  fissures,  the  edges  of  which  are 
kept  closed  by  the  adhesion  of  the  pia  mater. 

The  fissures  are  interposed  between  the  laminae  or  convolu- 
tions of  the  cerebellum,  which,  for  the  most  part,  are  concen- 
tric; the  larger  are  behind,  while  the  shortest  are  in  front,  near 
the  annular  protuberance.  The  pia  mater  penetrates  to  the  bot- 
tom of  these  fissures,  some  of  which,  when  exposed  fully  by  its 
removal,  are  found  to  extend  to  the  depth  of  an  inch  or  more. 


352  NERVOUS  SYSTEM. 

One  of  these  fissures,  which  exists  on  the  superior  surface  of 
the  cerebellum,  half  an  inch  distant  from  the  posterior  and  ex- 
ternal margin  of  the  latter,  has  a  circular  course,  and  is  so  well 
marked  by  its  size  and  depth,  that  it  is  called  the  Sulcus  Supe- 
rior Cerebelli.  Another,  situated  under  similar  circumstances 
on  the  inferior  surface  of  the  cerebellum,  is  called  the  Sulcus 
Inferior  Cerebelli.  On  the  latter  surface,  also,  there  are  two  or 
three  more  of  a  middle  size,  situated  between  the  sulcas  infe- 
rior and  the  tuber  annulare.  These  larger  sulci  have  given  oc- 
casion to  anatomists  to  multiply  most  unreasonably  the  number 
of  lobes  of  which  the  cerebellum  consists.  Bichat's  mode  of 
description  is  preferable:  he  says,  that  by  cutting  (vertically) 
through  one  of  the  hemispheres  of  the  cerebellum,  so  as  to  ex- 
pose the  thickest  part  of  its  medullary  matter,  that  six  or  seven 
principal  fissures  will  be  seen,  which,  by  penetrating  to  a  con- 
siderable depth,  divide  the  cineritious  portion  into  as  many  con- 
verging parts.  In  the  interior  of  these  fissures  there  are  much 
smaller  ones,  which  pass  at  right  angles  to  them.  On  the  sur- 
face or  periphery  of  the  cerebellum,  in  the  intervals  of  the 
larger  fissures,  there  are  many  small  ones,  which,  though  near- 
ly horizontal,  terminate  in  each  other  by  acute  angles. 

The  superior  middle  ridge  of  the  cerebellum,  from  its  shape 
and  position,  is  called,  by  Vicq.  D'Azyr,  Vermis  Superior;  the 
anterior  extremity  of  which,  from  its  elevation,  is  the  Monti- 
culus  Cerebelli. 

The  middle  inferior  part  of  the  cerebellum,  which  presents 
the  deep  sulcus  running  longitudinally  and  forming  the  divi- 
sion into  hemispheres,  has  a  long  ridge  occupying  the  sulcus. 
This  ridge  is  the  Vermis  Inferior  of  Vicq.  D'Azyr,  and  is  so 
concealed  by  the  adjacent  portions  of  the  hemispheres,  that  a 
good  view  of  it  can  be  got  only  by  removing  the  pia  mater  and 
pushing  the  hemispheres  aside.  The  transverse  fissures  which 
penetrate  it,  and  its  general  irregularity  of  surface,  will  then  be 
sufficiently  distinct.  The  pia  mater  passes  from  the  fore  part 
of  this  body  to  the  medulla  oblongata,  and  thus  assists  in  form- 
ing the  floor  of  the  fourth  ventricle;  which,  without  this  reflec- 
tion, would  be  exposed.  The  central  part  of  the  cerebellum  as 
formed  by  the  vermis  superior  and  by  the  vermis  inferior,  is 
the  Fundamental  Portion  of  Gall  and  Spurzheim. 


THE  CEREBELLUM.  353 

The  Valve  of  Vieussens  (Velum  Medullare,  Valvula  Cerebri) 
arises  from  the  cerebellum,  just  under  the  anterior  part  of  the 
base  of  the  monticulus,  and  runs  obliquely  upwards  to  terminate 
in  the  testes.  Sometimes  it  is  marked,  in  its  middle,  by  a  lon- 
gitudinal line  or  slight  fissure,  from  either  side  of  which  proceed 
small  lateral  ones.  It  is  principally  medullary,  and  has  a  small 
quantity  of  cineritious  matter  at  its  extremities.  It  is  thinner  in 
the  middle  than  at  either  of  its  margins. 

At  the  root  of  the  crus  cerebelli  are  two  small  protuberances ; 
the  one  below  it,  in  the  erect  position,  is  the  Lobulus  Amygda- 
loides,  and  the  other  the  Lobulus  Nervi  Pneumogastrici. 

The  substance  of  the  cerebellum  is  formed  of  cineritious  mat- 
ter externally,  and  of  medullary  matter  internally.  When  a 
vertical  section  of  it  is  made  through  the  middle  of  one  of  its 
hemispheres,  the  medullary  matter  puts  on  the  appearance  of 
the  thuya  or  arbor  vitas,  the  roots  and  ramifications  of  whose 
limbs,  even  to  their  smallest  extremities,  are  surrounded  by  ci- 
neritious matter.  In  this  view,  there  appears  to  be  more  cineri- 
tious than  white  matter;  but  when  a  horizontal  cut  is  made 
from  the  periphery  to  the  centre,  parallel  with  one  of  the  deep 
concentric  fissures,  the  proportion  of  medullary  matter  seems  to 
to  be  much  more  considerable;  and  the  arbor  vitae  arrange- 
ment is  proved  to  depend  upon  the  laminae  of  medullary  matter 
radiating  from  the  centre,  or,  in  other  words,  from  the  massive 
medullary  trunk  in  the  interior  of  the  hemisphere  of  the  cerebel- 
lum. Each  of  these  radiations  commences  by  a  root  of  consi- 
derable size,  which  divides  and  subdivides  into  branches.  Each 
primitive  radiation,  as  well  as  its  branches,  is  covered  by  its  own 
layer  of  cineritious  matter  about  one  line  in  thickness,  and  is 
kept  perfectly  distinct  from  the  contiguous  ones  by  the  fissures 
which  extend  internally  from  the  periphery  of  the  cerebellum. 

In  the  middle  of  the  trunk  of  the  arbor  vitas,  exists  the  Corpus 
Rhomboideurn,  or  Dentatum.  It  is  an  oblong  rounded  body, 
and  jagged  and  cineritious  in  its  circumference,  but  medullary 
within.  Its  configuration  resembles  that  of  the  corresponding 
body  in  the  eminentia  olivaris,  with  the  addition  of  its  being  larger, 
and  having  its  outline  better  marked.  It  is  the  ganglion  of  the 
cerebellum  of  Gall  and  Spurzheim. 


354  NERVOUS  SYSTEM. 

The  Central  or  Fundamental  Portion  of  the  Cerebellum  ex- 
hibits also  very  clearly  the  arborescent  arrangement,  and  is  fur- 
nished with  about  seven  primitive  radiations,  coming  from  a 
medullary  trunk.  The  proportion  of  medullary  matter  to  corti- 
cal, is  less  in  it  than  in  the  hemispheres  of  the  cerebellum. 
Each  of  the  primitive  radiations  may  be  traced  to  some  particu- 
lar point  or  prominence  on  the  surface  of  the  fundamental*  por- 
tion, thus  forming  its  basis ;  but  this  study  is  more  curious  than 
useful,  though  several  anatomists  have  pursued  it. 

Three  medullary  fasciculi,  on  each  side,  have  now  been  traced 
to  the  cerebellum ;  one  of  these  is  the  continuation  of  the  corpus 
restiforme  of  the  medulla  oblongata ;  a  second  is  the  valvula 
cerebri ;  and  the  third,  the  Crus  Cerebelli,  which  joins  the  annu- 
lar protuberance.  The  two  first  fasciculi  belong  to  the  middle 
or  fundamental  portion  of  the  cerebellum;  they  are,  consequent- 
ly, situated  more  internally,  and  are  partially  concealed  by  the 
crus  cerebelli,  and  have  interposed  between  them  and  the  latter, 
the  Corpus  Rhomboideum,  or  Dentatum. 


SECT.  V. OF  THE  CEREBRUM. 

The  Cerebrum  weighs  about  three  pounds,  and  is  seven  times 
as  heavy  as  the  cerebellum.  It  is  ovoidal,  and  measures  about 
six  inches  in  its  antero-posterior  diameter,  five  inches  in  its  great- 
est breadth,  which  is  behind,  and  four  or  five  in  depth.  It  is 
separated  above  by  a  deep  fissure,  (Fissura  Longitudinalis,}  into 
two  equal  parts,  called  Hemispheres.  At  the  bottom  of  this  fis- 
sure, by  separating  the  contiguous  surfaces  of  it,  is  to  be  seen  a 
broad  lamina  of  medullary  matter,  passing  from  side  to  side, 
and  called  the  Corpus  Callosum,  which  connects  the  two  .hemi- 
spheres together.  The  under  surface  of  each  hemisphere  is 
subdivided  into  three  lobes ;  Anterior,  Middle,  and  Posterior. 

The  anterior  lobes  are  placed  upon  the  anterior  fossae  of  the 
base  of  the  cranium;  the  Middle,  upon  the  middle  fossae  of  the 
same;  and  the  Posterior  Lobes  rest  upon  the  tentorium.  The 
two  anterior  lobes  are  completely  separated  by  the  Fissura 
Longitudinalis,  which  extends  between  them  to  the  base  of  the 


THE  CEREBRUM.  355 

cranium;  the  same  is  the  case  with  the  posterior  lobes;  the 
middle  lobes  have  interposed  between  them  the  annular  protu- 
berance and  the  crura  cerebri.  When  the  pia  mater  is  removed, 
the  anterior  lobe  is  seen  to  be  marked  off  from  the  middle  lobe 
by  a  deep  sulcus,  the  fissure  of  Sylvius,  in  the  under  surface  of 
the  cerebrum,  corresponding,  in  its  position,  with  the  posterior 
margin  of  the  Lesser  Sphenoidal  Wing.  The  boundary  between 
the  middle  and  the  posterior  lobe  is,  by  no  means,  well  defined 
on  the  basis  of  the  brain,  but  it  is  agreed  to  consider  as  posterior 
lobe,  all  that  part  of  the  hemisphere  which  rests  upon  the  tento- 
rium. 

The  periphery  of  the  cerebrum  is  formed  into  convolutions, 
(Gi/ri,)  which  give  it  an  unequal  tortuous  surface,  resembling 
the  intestines  of  a  small  child.  These  convolutions  are  sepa- 
rated by  fissures  (Sulci)  of  depths  varying  from  an  inch  to  two 
inches  or  more.  The  convolutions  proceed  in  diversified  and 
complicated  courses,  which  never  correspond  in  different  indi- 
viduals, and  seldom  on  the  two  hemispheres  of  the  same  brain. 
Though  their  summit  is  generally  convex,  yet  some  of  them 
have  it  depressed  slightly,  which  is  considered  a  proof  of  each 
convolution  being  divisible  into  two  halves  or  layers,  placed  side 
by  side.  Some  of  the  convolutions  are  short,  others  long;  they 
present  numerous  varieties  in  the  manner  of  joining  each  other. 
Owing  to  the  narrowness  of  the  fissures  between  them,  they  are 
closely  packed  together,  so  that  the  lateral  surfaces  of  each  one 
are  suited  to  such  as  are  contiguous:  occasionally,  there  is  a 
departure  from  this  rule. 

The  surface  of  the  convolution,  by  which  we  mean  not  only 
the  most  exterior  periphery  of  the  cerebrum,  but  also  the  surface 
formed  by  the  fissures  to  their  very  bottom,  is  covered  by  cine- 
ritious  matter  of  about  one  line  in  thickness. 

Within  the  periphery  of  the  cerebrum,  the  mass  of  medullary 
matter  is  very  considerable,  and  is  of  an  ovoidal  shape.  This 
ovoid  is  called  the  Centrum  Ovale  of  Vieussens,  and  is  brought 
fairly  into  view  by  making  a  horizontal  cut  through  the  hemi- 
spheres, two  inches  below  their  summit. 

In  proceeding  with  the  anatomy  of  the  cerebrum  from  its 
base  upwards,  the  following  is  the  order  or  succession  of  parts 


356  NERVOUS  SYSTEM. 

in  its  structure :  In  advance  of  the  pons  varolii,  and  springing 
from  it,  there  are  two  divergent  medullary  trunks,  one  on  each 
side,  which  run  forwards,  and  are  lost  in  the  medullary  sub- 
stance of  the  cerebrum.  These  trunks  are  the  crura  cerebri, 
upon  the  upper  surface  of  which  are  two  protuberances :  the  pos- 
terior is  the  thalamus  nervi  optici,  and  the  anterior  is  the  corpus 
striatum.  Each  crus  cerebri,  having  penetrated  into  the  sub- 
stance of  its  respective  hemisphere,  expands  by  a  multiplication 
of  the  filaments  composing  it,  so  as  to  constitute  the  principal 
bulk  of  the  hemisphere.  These  filaments  may,  indeed,  be  traced 
very  satisfactorily  in  almost  every  direction  towards  the  peri- 
phery of  the  cerebrum,  where  they  terminate  in  the  convolu- 
tions, their  extremities  being  covered  by  the  cineritious  matter 
there.  The  arrangement  is  best  seen  by  scraping  with  a  knife 
along  the  base  of  the  brain,  especially  when  the  latter  has  been 
hardened  in  spirits  of  wine,  and  it  is  constituted  by  what  are 
called,  by  MM.  Gall  and  Spurzheim,  the  diverging  fibres  of  the 
brain. 

The  point  is  not,  indeed,  entirely  settled  that  the  diverging 
filaments  end  in  the  convolutions,  or  do  not  rather  afterwards 
inflect  or  double  on  themselves,  and  pass  inwards  again  to  the 
middle  line  of  the  brain,  forming,  by  their  convergence,  the  cor- 
pus callosum.  At  all  events,  the  fact  is  quite  demonstrable,  that 
as  the  under  and  lateral  portions  of  the  hemisphere  consist  in 
diverging  filaments,  arising  in  and  from  the  crus  cerebri,  so  the 
upper  portion  and  the  corpus  callosum,  consist  in  filaments  which 
arise  in  the  adjoining  convolutions,  and  collect  towards  the  mid- 
dle line  of  the  corpus  callosum,  where  they  adhere  to  the  con- 
generic filaments  of  the  other  side. 

The  arrangement,  in  the  most  simple  conception  and  illustra- 
tion of  it,  would  be  exemplified  by  folding  a  strip  of  cloth  double 
on  itself,  so  as  to  convert  it  into  a  loop ;  the  under  part  of  the 
loop  would  then  represent  the  diverging  fibres  of  the  cerebrum 
and  the  upper  part  the  converging  fibres,  or  corpus  callosum ; 
it  being  at  the  same  time  borne  in  mind  that  the  continuation  of 
the  two  orders  of  fibres  into  one  another  in  the  brain  is  not  so 
fully  ascertained  as  it  would  be  represented  by  this  model. 

Between  the  two  orders  of  fibres  there  is  a  horizontal  cleft  or 
interval.  This  interval  is  the  lateral  ventricle  of  the  hemisphere, 


TIJE  CEREBRUM.  35? 

which  may  be  got  into  under  the  posterior  margin  of  the  corpus 
callosum,  from  its  being  open  there,  or  rather  only  closed  by  an 
adhesion  of  the  membranes,  which  is  easily  lacerated. 

The  preceding  is  intended  as  a  mere  outline  upon  which  to 
form  the  base  of  the  descriptive  anatomy  of  the  cerebrum. 
The  following,  therefore,  may  be  considered  as  the  detailed 
account : — 

The  Crura  Cerebri  are  rounded  below ;  are  about  eight  lines 
long,  and  increase  in  their  transverse  diameter  as  they  advance; 
their  vertical  diameter  is  about  ten  lines.  They  mutually  di- 
verge, beginning  from  their  roots,  and  are  separated  by  a  deep 
fissure,  considered  as  a  continuation  of  that  on  the  front  of  the 
medulla  oblongata.  This  fissure  is  the  third  ventricle  of  the 
brain.  Their  surface  is  marked  by  superficial  furrows,  running 
longitudinally ;  and  about  two  lines  before  the  tuber  annulare, 
by  a  transverse  fasciculus  of  medullary  matter,  very  slightly 
elevated:  the  optic  nerves  also  cross  them  obliquely  at  their  fore 
part. 

In  regard  to  texture,  the  crus  cerebri  presents,  on  its  under 
surface,  a  medullary  layer  of  two  lines  in  thickness ;  to  this  suc- 
ceeds a  parcel  of  cineritiaus  matter,  which,  on  being  removed, 
is  followed  by  a  mixture  of  both  cineritious  and  white  matter, 
more  abundant  than  either  of  the  preceding. 

The  Eminentiae  Mammillares,  or  Corpora  Albicantia,  are  two 
small  bodies,  one  on  each  side,  about  the  size  of  a  French  pea. 
They  are  situated  near  the  anterior  extremities  of  the  crura  ce- 
rebri, on  their  internal  faces,  and  almost  in  contact  with  each 
other.  Their  texture  is  medullary  without,  and  cortical  within. 

The  Infundibulum  is  placed  immediately  before  the  eminen- 
tiae  mammillares.  It  is  a  flattened  conoidal  body,  half  an  inch 
long,  with  its  base  upwards,  and  its  apex  going  downwards  and 
forwards.  It  is  formed  of  cineritious  matter.  Most  generally 
its  base  is  hollow,  and  opens  into  the  third  ventricle,  but  its  point 
is  closed.  J.  F.  Meckel,  however,  asserts  that  a  communication 
exists  entirely  through  it,  from  the  pituitary  gland  to  the  third 
ventricle,  and  that  lie  has  (frequently  proved  it  by  passing  air  or 
VOL.  II.— 46 


NERVOUS  SYSTEM. 

liquids  from  this  gland,  though  the  experiment  does  not  succeed 
When  he  attempts  the  injection  from  the  third  ventricle. 

The  Pituitary  Gland  (Glandula  Piluitaria)  is  situated  in  the 
Sella  Turcica,  and  is  covered  so  completely  by  the  dura  mater, ' 
that  only  a  small  aperture  is  left  for  the  point  of  the  infundibu- 
lum  to  pass  through  and  to  adhere  to  it.  It  is  an  ovoidal  body, 
the  greatest  diameter  of  which  is  transverse,  and  amounts  to 
^six  lines.  It  is  partially  divided,  so  as  to  give  the  appearance 
'of  two  lobes,  of  which  the  anterior  is  much  the  larger.  It  is 
hard  and  cineritious,  with  a  small  quantity  of  medullary  matter 
Within.  In  either  side  of  it  there  is  a  depression  from  wThich 
leads  a  small  canal  towards  the  place  where  the  infundibulum 
joins  it :  the  two  canals  are,  in  the  latter  place,  united  into  one. 
5n  sortie  very  rare  Cases,  gritty  matter  has  been  found  in  h% 
as  there  is  in  the  pineal  gland.  It  is  also  surrounded  by  pia 
mater. 

The  Tuber  Cinereum,  or  Pons  Tarini,  is  a  portion  of  the  un- 
der surface  of  the  crura  cerebri,  at  the  floor  of  the  third  ventri- 
'cle.    It  is  continuous  in  front  with  the  anterior  margin  of  the 
corpus  callosum.     In  front  of  the  infundibuhfm  the  optic  nerves 
unite,  after  having  crossed    obliquely  the   crura  cerebri  from 
without  inwards  and  forwards.  In  this  passage,  where  they  reach 
"the  middle  of  the  crura,  and  at  the  internal  border  of  the  same-, 
they  come  in  contact  with  the  tuber  cinereum,  from  which  they 
get  a  few  filaments;  but  of  this,  more  hereafter. 

The  Thalami  Optici,  called,  by  Gall,  the  Posterior  Ganglions 
•t)f  the  brain,  (Ganglia  Postiva,)  are  amongst  the  most  conspi- 
cuous parts  of  the  internal  stracture  of  the  cerebrum,  and  are 
two  in  number,  one  for  either  side.  They  are  situated  on  the 
superior  face  of  the  crura  cerebri,  are  about  an  inch  and  a  half 
long  from  behind  forwards,  and  abotit  eight  or  ten  lines  broad 
">and  deep. 

The  thalami  are  convex  above  and  internally.  At  the  junc- 
tion of  these  two  surfaces  is  observed  a  medullary  line,  de- 
scribed under  the  name  of  peduncle  of  the  pineal  gland.  Their 
.posterior  extremity  is  likewise  convex,  and  is  divided  into  three 


THE  CEREBRUM;  359 

rounded  prominences;  one  is  above  the  other  two-,  and  is  the 
Tuberculum  Posterius  Superius;  the  second  is  below  and  with- 
in, (Corpus  Geniculatum  Inter  num,)  and  the  third  is  below 
and  external,  (Corpus  Geniculatum  Externum.}  There  is  a 
fourth  tubercle  (Tuberculum  JJnterius)  which  is  situated  on 
the  upper  convex  surface  of  the  thakimus;  it  is  produced  by  the 
fan-like  termination  of  a  large  medullary  fasciculus  which  comes 
from  the  eminentia  mammillaris. 

The  thalami  are  somewhat  flattened  on  the  middle  of  their 
convex  internal  surface,  and  adhere  there  to  each  other  by  a 
layer  of  cineritiou^  substance,  called  Commissura  Mollis.  When 
the  brain  is  very  slightly  advanced  in  putrefaction,  or  has  been 
made  soft  by  dropsy,  this  junction  scarcely  seems  to  exist  at  all. 

The  thalami  are  medullary  on  the  surface  presented  to  the 
ventricles  of  the  brain,  but  within  they  are  a  mixture  of  cin>eri- 
tious  with  medullary  matter.  The  fibres  of  the  medullary  are 
very  intimately  blended  with  the  crura  cerebri,  and  radiate  from 
within  towards  the  circumference  of  the  brain:  some  of  them 
are  placed  in  layers,  and  are  connected  with  the  tubercula  quad-* 
rigemina. 

The  Corpora  Striata,  or  the  Ganglia  Cerebri  Antica,  also  two 
in  number,  one  for  each  side  or  hemisphere  of  the  brain,  are 
situated  before  the  thalami  optici,  at  the  bottom  of  the  lateral 
ventricles.  They  are  about  two  and  a  half  inches  long,  convex 
on  their  upper  surface,  and  eight  line*  broad  at  their  front  part, 
but  taper  very  gradually  to  a  point  behind.  They  are  about  four 
lines  apart  in  front,  and  are  separated  there  by  the  septum  lu- 
cidum,  but  their  posterior  extremities  diverge  from  each  other, 
so  as  to  admit  the  thalami  optici  between  them. 

The  surface  of  the  corpus  striatum  is  cineritious,  but  within 
it  consists  of  cineritious  and  of  medullary  matter,  placed  in  lay- 
ers which  alternate  with  each  other.  These  layers  are  arranged 
in  a  crescentic  manner,  so  as  to  present  the  convexity  upwards 
and  the  concavity  downwards.  The  medullary  substance  is  a 
continuation  of  that  of  the  crus  cerebri  and  of  the  optic  thala- 
mus.  It  enters  at  the  posterior  inferior  part  of  the  corpus  stri- 
atum, and  immediately  divides  into  three  layers,  placed  one 
above  the  other,  and  of  which  the  two  inferior  are  more  narrow 


360  NERVOUS  SYSTEM. 

• 

and  short  than  the  superior.  The  upper  layer,  in  its  progress 
forwards,  is  interrupted  by  a  body  of  cineritious  substance,  which 
occasions  it  to  divide  into  a  multitude  of  distinct  radiated  fibres. 
The  same  circumstance  attends  the  other  layers,  but  in  a  more 
limited  degree.  The  medullary  matter  of  the  corpus  striatum 
may  then  be  traced,  in  all  directions,  into  the  hemisphere  of  the 
brain.  The  cineritious  substance  of  the  corpus  striatum  is  abun- 
dant, and  is  divided  by  some  anatomists  into  two  kinds,  one  of 
a  light  gray,  and  another  of  a  darker  colour.  The  first  forms 
the  middle  and  inferior  part  of  the  corpus  striatum;  the  second 
is  in  greater  quantity,  and  is  found  principally  above  and  be- 
tween the  two  upper  layers.  Such  is  the  general  plan  of  the 
structure  of  the  corpus  striatum;  but,  it  should  also  be  under- 
stood, that  a  close  intertexture  exists  between  its  medullary  and 
cineritious  matter. 

The  most  satisfactory  way  of  unravelling  the  structure  of  the 
corpus  striatum,  is  to  scrape  away  its  under  surface,  in  tracing 
its  medullary  matter  from  the  crus  of  the  brain,  and  through 
the  optie  thalamus.  It  will  then  be  seen,  that  the  medullary 
substance  of  the  crus  reaches  the  posterior  inferior  part  of  the 
corpus  striatum,  and  is  immediately  invested  in  the  greater 
part  of  its  circumference  with  cineritious  matter,  it  then  begins 
to  expand  after  the  manner  of  a  fan  into  filaments.  These  fila- 
ments or  fasciculi  penetrate  the  cineritious  matter  in  various 
directions,  besides  those  just  detailed.  A  particular  exposition 
of  them  is  given  by  GalPand  Spurzheim,  in  their  anatomy  of 
the  brain. 

The  Taenia  Striata  is  placed  in  the  angle  formed  between 
the  internal  margin  of  tfie  Corpus  Striatum,  and  the  external 
one  of  the  Thalamus  Opticus,  where  these  two  bodies  are  in 
contact  and  continuous  with  one  another.  It  is  a  small  medul- 
lary band,  not  a  line  in  breadth,  commencing  near  the  anterior 
crus  of  the  fornix,  with  which  it  is  connected  frequently  by  fila- 
ments; and  observing  the  curved  course  of  the  fissure  in  which 
it  is  placed,  it  goes  to  the  posterior  end  of  the  corpus  striatum, 
and  even  beyond  it  in  most  cases,  by  uniting  itself  to  the  top  of 
the  Cornu  Ammonis. 

The  Corpus  Callosum.     When  the  fissure  between  the  he- 


THE  CEREBRUM.  361 

mispheres  of  the  cerebrum  is  widely  separated,  or  when  the  su- 
perior part  of  the  hemisphere  is  cut  away  on  a  level  with  the 
bottom  of  the  fissure,  the  Corpus  Callosum,  a  medullary  layer, 
is  brought  fully  into  view.  This  body  unites  the  medullary 
mass  of  the  two  hemispheres,  and  is  a  large  commissure.  It 
occupies  about  two-fifths  of  the  long  diameter  of  the  brain,  be- 
ing nearer  to  its  anterior  than  to  its  posterior  end,  and  is  about 
eight  lines  broad:  increasing,  however,  somewhat  in  breadth 
posteriorly.  The  lateral  half  of  it,  on  either  side,  is  concealed 
by  the  hemisphere  overlapping  it,  but  is  prevented  from  ad- 
hering by  a  horizontal  fissure  which  extends  from  one  end  to  the 
other.  It  has  an  arched  form,  being  convex  above  and  concave 
below.  Its  thickness  is  uniformly  about  three  lines,  with  the 
exception  of  its  anterior  and  its  posterior  margins,  which  are 
more. 

The  middle  line  of  its  upper  surface  is  marked  out  from  one 
end  to  the  other  by  a  very  slight  depression,  the  Raphe;  on 
each  side  of  which  there  is  a  very  small  linear  elevation  of  the 
same  extent,  but  slightly  curved  inwards  towards  its  fellow. 
From  these  longitudinal  lines  there  proceed  outwardly  trans- 
verse ones,  having  a  fibrous  appearance.     At  the  anterior  and 
posterior  ends  of  the  corpus  callosum,  the  latter  are  somewhat 
curved  and  radiated  towards  the  periphery  of  the  brain.    Other 
longitudinal  lines  also  exist  on  the  surface  of  the  corpus  callo- 
sum, but  they  are  not  seen  with  equal  facility.     The  anterior 
extremity  of  the  corpus  callosum  is  rounded  off,  and  bent  down- 
wards towards  the  basis  of  the  brain,  in  such  a  manner  as  to 
present  backwards  its  concavity;  which  thus  embraces  the  fore 
part  of  the  corpora  striata,  and  closes  the  lateral  ventricles  at 
this  point.    The  posterior  end  of  the  corpus  callosum  is  rounded, 
also,  and  continuous  with  the  fornix  and  with  the  cornu  ammonis. 
By  examining  the  Corpus  Callosum  from  below,  or  by  look- 
ing at  its  relative  situation  and  shape  on  a  hemisphere  which  is 
accurately  separated  from   its  fellow  in  the  middle  line,  it  will 
be  seen  that  its  lower  surface  is  very  concave,  being  highly 
arched  from  before  backwards;  that  it  forms  the  roof  of  the  la- 
teral ventricles,  and  that  this  surface  of  it  is  about  two  inches 
in  its  transverse  diameter,  and,  therefore,  more  than  twice  as 
broad  as  the  upper  surface. 


362  NERVOUS  SYSTEM. 

The  Fornix  (Trigone  Cerebral,  of  the  French)  is  placed  im- 
mediately below  the  corpus  callosum.  It  is  a  triangular  body 
of  the  medullary  matter,  the  base  of  which  is  behind  and  the 
apex  in  front.  It  is  about  an  inch  and  a  half  long  in  its  body, 
and  one  inch  wide  at  its  base.  It  is  the  latter  part,  which,  ly- 
ing immediately  beneath  the  posterior  end  of  the  corpus  callo- 
sum, is  continuous  with  it,  and  causes  the  fornix  to  be  consi- 
dered as  a  part  of  the  same  structure  with  the  corpus  callosum. 
These  two  bodies,  which  may  be  compared  to  a  sheet  of  me- 
dullary matter  doubled  on  itself,  have  their  surfaces  in  contact 
for  a  short  distance  behind,  the  fornix  afterwards,  by  advancing 
and  keeping  itself  in  close  contact  with  the  thalami  nervorum 
opticorum,  which  are  just  below  it,  diverges  more  and  more 
from  the  under  surface  of  the  corpus  callosum.  It  conceals  all 
the  upper  surface  of  the  thalami  except  their  external  margins, 
and,  having  reached  their  anterior  extremities,  its  apex  de- 
scends towards  the  basis  of  the  brain. 

The  body  of  the  fornix  is  about  a  line  thick,  but,  at  its  ante- 
rior extremity,  it  becomes  somewhat  cylindrical,  and  is  divided 
into  two  columns,  called  Crura  Fornicis  Anteriora.  Each  of 
these  crura,  in  descending  adheres  to  the  anterior  extremity  of 
the  thalamus  of  that  side,  and,  getting  finally  below  it  into  the 
floor  of  the  third  ventricle,  it,  after  a  course  slightly  curved, 
joins  the  cortical  substance  of  the  Eminentiae  Mammillares. 
Santorini,  aware  of  this  junction,  considered  the  emineyntiae 
as  a  part  of  the  fornix,  and,  therefore,  called  them  Bulbi  For- 
nicis. 

The  fornix  has  other  attachments  of  a  more  complex  descrip- 
tion, which  the  anatomist  should  attend  to,  as  they  serve  to 
indicate  the  modes  of  intercourse  between  the  several  parts  of 
the  cerebrum.  Its  fibres  having  reached,  and  probably  formed, 
the  eminentiae  mammillares:  one  fasciculus  of  them  ascends 
from  thence  along  the  internal  face  of  the  optic  thalamus,  in- 
vested by  the  cineritious  matter  of  the  latter,  and  spreads  it- 
self above  like  a  fan,  and  forms  the  tuberculum  anterius:  a  se- 
cond fasciculus  from  the  same  point,  having  divided  into  two, 
after  going  a  short  distance,  sends  one  division  backwards 
along  the  upper  internal  face  of  the  optic  thalamus,  to  join 


THE  CEREBRUM.  363 

the  peduncle  of  the  pineal  gland,  and  the  other  division,  which 
is  more  anterior,  runs  to  join  the  taenia  striata;  a  third  fasci- 
culus from  the  eminentia  mammillaris,  being  covered  by  the 
optic  nerve,  goes  outwards  and  backwards  to  terminate  in  the 
thalamus. 

'The  posterior  margin,  or  the  base  of  the  fornix,  besides  run- 
ning into  the  Corpus  callosum,  has  the  angle  on  each  side  elon- 
gated so  as  to  rest  upon  and  to  join  the  upper  end  of  the  cornu 
ammonis.  The  angle,  being  continued,  then  follows  the  wind- 
ing course  of  the  latter,  adhering  to  its  posterior  margin,  but 
hanging  loosely  over  the  anterior.  This  loose  edge  or  continu- 
ation of  the  external  margin  of  the  fornix  is  the  Tsenia.  Hippo- 
campi, or  Corpus  Fimbriatum  of  the  Lateral  Ventricle.  The 
elongations  of  the  posterior  angles  are  called  Crura  Posteriora 
Fornicis.  In  the  brains  of  individuals  who  have  suffered  from 
general  dropsy,  one  frequently  finds  the  fornix  narrower  than 
usual,  and  in  its  middle  a  fissure  which  separates  almost  com- 
pletely its  two  halves. 

As  the  fornix  is  fitted  to  the  upper  surface  of  the  optic  tha- 
lami,  it  is  of  course  concave  below  and  convex  above,  or  resem- 
bles a  triangular  arch  resting  upon  its  three  points  or  angles. 
Owing  to  some  misunderstanding  of  the  original  Greek  word 
***<&$,  which,  according  to  the  interpretation  of  Sabatier, 
means  a  vault,  and  thereby  expresses  the  whole  body,  anato* 
mists,  with  the  exception  of  him,  have  generally  supposed  the 
striated  under  surface  of  the  fornix  to  be  meant  by  it,  and 
have  called  the  surface  Lyra,  in  which  mistake  one  has  followed 
another.  / 

The  Septum  Lucidnm  is  a  partition  placed  vertically  in  the 
middle  line  of  the  brain,  and  extends  from  the  corpus  callosum 
above  to  the  fornix  below.  It  is  of  a  triangular  shape,  but  ir- 
regularly so,  being  much  broader  before  than  it  is  behind,  and 
having  its  edges  so  incurvated  as  to  fit  the  bodies  against  which 
it  is  applied. 

The  septum  lucidum  is  formed  by  two  lamina  placed  side  to 
but  not  adhering  to  each  other,  and  leaving,  therefore,  an 
interval  between  them,  called  the  Ventriculus  Septi,  or  the  fifth 
ventricle.  Each  of  these  laminae  consists  of  two  layers;  the 


364  NERVOUS  SYSTfcM. 

internal  is  medullary  substance,  continuous  with  that  of  the  cor* 
pus  callosum  and  of  the  fornix;  and  the  external  is  a  layer  of 
cineritious  substance.  The  cavity  is  about  an  inch  and  a  half 
long  by  a  line  wide,  and  is  narrower  in  the  middle  than  at  either 
extremity.  It  is  lined  by  a  delicate  serous  membrane,  which 
becomes  manifest  when  the  halitus  that  naturally  covers  its  sur- 
face is  accumulated  into  a  body  of  water.  It  is  generally  sup- 
posed to  be  insulated  or  completely  shut  up,  yet  occasionally  it 
has  been  found  elongated  in  front,  towards  the  space  between 
the  anterior  commissure  and  the  anterior  crura  fornicis,  and  to 
communicate  there  with  the  third  ventricle.* 

The  Pineal  Gland  (Glandula  PineaZis,  Conttrium)  is  placed 
beneath  the  posterior  margin  of  the  fornix,  upon  the  superior  of 
the  tubercula  quadrigemina,  or  the  nates.  It  is  an  oblong  conoi- 
dal  body,  the  long  diameter  of  which  is  transverse,  and  amounts 
to  three  or  four  lines,  while  the  short  diameter  is  about  three 
lines.  These  diameters  are,  however,  sometimes  reversed.  The 
substance  of  the  pineal  gland  is  cineritious,  and  of  a  reddish  co- 
lour. At  its  inferior  part  there  is  a  small  cavity,  sometimes 
lined  with  medullary  matter,  and  the  orifice  of  which  looks  to- 
wards the  third  ventricle. 

This  body  is  connected  to  the  adjacent  parts  by  several  cords. 
From  its  bottom  there  proceeds,  on  each  side,  the  long  medul- 
lary filament,  called  its  peduncle,  which  runs  along  the  upper 
internal  face  of  the  thalamtis  opticus,  and,  as  observed,  joins,  or 
is  continuous  with,  one  of  the  filamentous  processes  from  the 
Eminentia  Mammillaris.  From  its  base  there  proceeds  a  trans- 
verse lamina  of  medullary  matter,  called  the  Posterior  Commis- 
sure of  the  brain,  which  first  advances  forwards,  and  then  re- 
cedes, so  as  to  be  in  some  measure  doubled  on  itself.  This  la- 
mina, at  either  end,  is  united  to  the  upper  posterior  part  of  the 
corresponding  optic  thalamus,  and  by  its  lower  margin  runs  into 
the  superior  edge  of  the  tubercula  quadrigemina. 

Frequently,  within  the  pineal  gland,  and  sometimes  on  its 
surface,  there  is  an  accumulation  of  calcarious  matter,  the  Acer- 
vulus  Cerebri,  that  appears  about  the  sixth  year  of  life,  and  con- 

*  J.  F.  Meckel. 


THE  CEREBRUM.  365 

tinues  for  ever  afterwards.  It  is  variable  both  in  quantity  and 
in  its  mode  of  concretion,  for  sometimes  there  are  only  a  few 
atoms  of  grit,  scarcely  distinguishable  by  the  feel;  while,  on 
other  occasions,  it  is  collected  into  a  body  of  irregular  shape, 
and  more  than  a  line  in  diameter.  The  pieces  of  which  the 
acervulus  consists  are  sometimes  united  by  cellular  substance, 
and  enclosed  in  a  sac.  The  chemical  analysis  presents  phos- 
phate of  lime  in  large  proportion,  carbonate  of  lime,  and  ani- 
mal matter. 

A  reflection  of  pia  mater,  called  the  Velum  Interpositum,  se- 
parates the  pineal  gland  from  the  fornix,  and  the  fornix  from  the 
thalami  nervorum  opticorum. 

The  Tubercula  Quadrigemina  (or  the  Nates  et  Testes)  are 
situated  on  the  superior  face  of  the  crura  cerebri,  and  just  be- 
hind the  thalami  nervorum  opticorum.  A  very  complete  view 
of  them  is  obtained  by  separating  the  posterior  lobes  of  the  ce- 
rebrum, and  by  paring  off  the  vermis  superior  cerebelli.  Though 
the  name  implies  four  distinct  prominences,  yet  they  are  formed 
from  a  common  mass  of  nine  or  ten  lines  square,  on  the  poste- 
rior surface  of  which  these  prominences  arise.  They  are  in 
pairs,  and  are  separated  from  one  another  by  a  crucial  depres- 
sion. The  largest,  or  upper  pair,  is  the  Nates,  the  lower  pair 
the  Testes.  The  external  surface  of  these  bodies  is  medullary, 
and  within  they  are  cineritious.  From  the  Nates  there  pro- 
ceeds a  considerable  medullary  fasciculus,  which  runs  forward 
to  join  the  Corpus  Geniculatum  Internum  on  the  internal  pos- 
terior face  of  the  thalamus  nervi  optici;  there  proceeds  also 
from  them  a  second  fasciculus,  which  either  joins  the  optic 
nerve  itself,  or  the  contiguous  part  of  its  thalamus.  The  Testes 
receive,  at  their  lower  end,  the  valve  of  the  brain;  and  there 
also  proceeds  from  them  a  large  fasciculus  of  medullary  matter, 
which  joins  the  Corpus  Geniculatum  Externum  of  the  optic 
thalamus. 


VOL.  II.— 47 


366  NERVOUS  SYSTEM. 

Of  the  Ventricles  of  the  Brain. 

These  cavities  are  four  in  number:  two,  called  lateral,  are 
placed  one  in  either  hemisphere  of  the  cerebrum,  a  third  is  be- 
tween the  two  thalami,  and  the  fourth  under  the  cerebellum. 
They  have  all  been  alluded  to,  but  only  incidentally. 

The  two  Lateral  Ventricles  ( Ventriculi  Laterales]  are  horizon- 
tal cavities,  or  fissures,  of  an  extremely  irregular  shape,  in  the 
very  centre  of  the  hemispheres,  being  the  interval  between  the 
diverging  and  converging  filaments  of  the  cerebrum.  They  are 
separated  from  each  other  only  by  the  septum  lucidum ;  are  co- 
vered over  by  the  corpus  callosum,  and  have  the  fornix,  thalami 
optici,  and  corpora  striata  for  a  floor.  Each  one  consists  in  a 
body  or  principal  cavity,  and  three  processes,  called  cornua. 
The  body  has  been  sufficiently  described  in  speaking  of  the  parts 
which  constitute  its  parietes;  but  the  processes  are  yet  to  be 
considered. 

The  Cornua,  from  their  position,  are  named  Anterior,  Poste- 
rior, and  Lateral  or  Inferior.  The  Anterior  is  a  very  small 
space  between  the  anterior  extremity  of  the  corpus  striatum  and 
the  opposite  surface  of  the  hemisphere,  and  has  nothing  in  it 
particularly  deserving  of  notice.  The  Posterior  Cornu  extends 
from  the  base  of  the  fornix  to  the  distance  of  an  inch  or  more  in 
the  substance  of  the  posterior  lobe  of  the  cerebrum.  Its  cavity 
is  conoidal,  somewhat  curved,  with  its  convexity  outwards,  and 
of  six  or  seven  lines  in  diameter  at  its  base.  Its  internal  side  is 
furnished  with  an  oblong  eminence  called  Hippocampus  Minor, 
or  Ergot,  from  its  resemblance  to  a  cock's  spur,  but  its  size  and 
form  are  somewhat  variable.  When  this  eminence  is  cut  through 
transversely,  it  is  easy  to  see  that  it  is  formed  by  a  convolution 
of  the  posterior  lobe  projecting  into  the  posterior  cornu.  The 
convolution  is  covered  by  medullary  matter  on  the  side  of  the 
ventricle,  and  of  course  by  cineritious  on  the  side  of  the  peri- 
phery of  the  brain,  and  is  the  bottom  of  an  anfractuosity. 

The  Inferior,  Middle,  or  Lateral  Cornu,  of  the  Lateral  ven- 
tricles is  situated  in  the  middle  lobe  of  the  cerebrum.  It  com- 


THE  CEREBRUM.  367 

mences  at  the  posterior  angle  of  the  fornix,  and  winds  down- 
wards and  forwards  in  a  semicircle  towards  the  fissure  of 
Sylvius,  presenting  its  convexity  outwards,  and  its-  concavity 
within.  Its  floor  is  furnished  in  its  whole  length  with  an  ele- 
vated ridge,  the  surface  of  which  is  semi-cylindrical.  This  ridge 
is  the  Cornu  Ammonis,  or  Hippocampus  Major,  and  increases 
somewhat,  both  in  breadth  and  elevation,  as  it  winds  down  the 
process  of  the  ventricle.  Its  lower  or  anterior  extremity  is  ter- 
minated by  two  or  three  small  tubercles,  and  is  the  Pes  Hip- 
pocampi. Occasionally  the  Hippocampus  Major  is  marked  off 
by  a  middle  longitudinal  fissure  into  two  elevations,  of  which  the 
external  is  the  smaller.  On  its  concave  side  there  is  the  thin 
edge  of  medullary  matter,  continuous  with  the  external  margin 
of  the  fornix.  The  extremity  of  a  knife  handle  may  be  insinuated 
for  a  short  distance  between  this  edge  arid  the  Hippocampus ;  it 
ceases  about  half  way  down  the  latter,  and  in  the  natural  state 
of  the  parts  is  concealed  by  the  plexus  choroides.  This  edge  is, 
as  mentioned  in  the  account  of  the  fornix,  the  Taenia  Hippocampi 
or  Corpus  Fimbriatum.  Beneath  the  latter,  and  partially  covered 
by  it,  there  is  another  body,  which  presents  itself  in  the  form 
of  a  small  chord  of  cineritious  matter,  is  not  quite  so  long  as  the 
Taenia,  and  is  called  Fascia  Dentata,  from  being  divided  into 
several  sections  by  transverse  ^fissures,  which  give  it  an  undu- 
lating appearance. 

A  transverse  incision  of  the  Hippocampus  Major  shows  that 
it  is  a  body  of  cineritious  matter,  covered  on  its  surface  by  a 
thin  layer  of  medullary  substance. 

The  Third  Ventricle,  ( Ventriculus  Tertius.)  When  the  fornix 
is  separated  from  its  anterior  crura  and  turned  over  backwards, 
the  process  of  pia  mater,  called  Velum  Interpositum,  is  found 
between  it  and  the  optic  thalami.  This  process  is  of  a  triangu- 
lar shape,  resembling  the  fornix,  and  is  about  the  same  size ;  it 
is  insinuated  into  this  place  from  the  surface  of  the  brain,  under 
the  posterior  margin  of  the  corpus  callosum.  Its  lateral  margins, 
which  project  beyond  the  corresponding  ones  of  the  fornix,  are 
formed  by  a  congeries  of  convoluted  vessels,  constituting  the 
plexus  choroides.  The  plexus,  indeed,  may  be  traced  from  the 
Hippocampi  along  the  corpus  fimbriatum  to  its  position  on  the 


368  NERVOUS  SYSTEM. 

margin  of  the  velum  interpositum ;  and  insinuates  itself  from 
the  bottom  of  the  cerebrum  between  the  pons  varolii  and 
the  convolution  forming  the  Hippocampus  Major;  but  when 
it  reaches  the  anterior  end  of  the  fornix  its  convoluted 
character  ceases,  and  it  terminates,  on  each  side,  in  a  single 
vein,  (Vena  Galeni,)  which  runs  from  before  backwards,  in  a 
straight  line,  near  the  middle  of  the  velum  interpositum.  The 
vein,  finally,  unites  with  its  fellow  to  form  a  single  trunk,  which 
runs  into  the  fourth  sinus  of  the  dura  mater. 

The  Velum  Interpositum,  or  Tela  Choroidea,  adheres  very 
strongly  to  the  fornix,  by  means  of  small  vessels :  it  may  be 
raised  with  less  difficulty  from  the  thalami,  though  it  serves  to 
keep  the  third  ventricle  closed  above,  with  the  exception  of  the 
part  just  behind  the  crura  of  the  fornix,  where  the  third  and  the 
lateral  ventricle  communicate  by  the  foramen  of  Monro.  The 
pineal  gland  is  entangled  in  its  posterior  part,  being  placed  be- 
low it,  and  js  generally  torn  from  its  peduncles  when  the  tela  is 
raised  up.  It  is  at  this  point  that  the  tunica  arachnoidea  may 
be  traced  into  the  cavity  of  the  lateral  ventricles,  according  to 
Bichat* 

The  Plexus  Choroides,  which  was  stated  to  bound  the  tela 
choroidea  on  each  side,  and  to  descend  along  the  Hippocampus 
Major  to  the  fissure  of  Sylvius,  or  rather  to  ascend  from  this 
point,  and  to  terminate  in  the  vein  on  the  side  of  the  middle  line 
of  the  tela,  is  narrow  at  its  termination,  but  increases  continually 
in  breadth  as  it  is  traced  towards  its  commencement.  The 
middle  part,  however,  where  it  makes  its  turn,  is  an  exception 
to  this  rule,  for  there  it  is  larger  in  every  way  than  elsewhere: 
its  vessels  being  more  capacious  and  more  tortuous.  Precisely 
at  this  point  a  vesicle  or  more  is  very  frequently  found,  consi- 
dered by  some  as  a  hydatid  of  the  brain;  in  some  cases  it  is 
filled  with  calcarious  matter  instead  of  with  water.  The  Glan- 
dulae  Pacchioni,  as  stated,  also  prevail  at  this  margin. 

On  the  under  surface  of  the  tela  choroidea,  adhering  to  it, 
there  is  on  each  side  a  small  venous  plexus  which  goes  from  be- 

*  Some  doubts  may  be  reasonably  raised  on  this  point  of  anatomy,  as  the  evi- 
dence is  seldom  or  never  satisfactoiy  to  the  full  extent,  and  as  such  an  arrange- 
ment would  be  contradictory  to  that  of  the  tunica  arachnoidea  on  the  surface  of 
the  brain,  as  it  never  dips  into  fissures. 


THE  CEREBRUM.  369 

fore  backwards,  and  terminates  in  the  vena  galeni,  near  its  junc- 
tion with  its  fellow.  It  receives  the  blood  of  the  third  and  of 
the  fourth  ventricle.* 

There  is  also  the  same  sort  of  plexus  in  the  fourth  ventricle. 

Upon  the  removal  of  the  Velum  Interpositum,  or  its  elevation, 
the  whole  upper  surface  of  the  thalami  optici  is  exposed.     The 
third  ventricle  is  also  brought  into  view,  being  placed  imme- 
diately between  the  thalami  optici.     It  is  a  narrow  oblong  cavi- 
ty, bounded  below  by  the  pons  tarini,  crura  cerebri  and  the 
eminentiae   mammillares,   and  above   by   the   velum   interposi- 
tum,  and  the  fornix.     The  anterior  crura  of  the  fornix  are  at  its 
fore  part,  and  just  before  them  is  the  anterior  commissure  (Com- 
missura   Anterior.}      This   body  is   a   transverse  fasciculus    of 
medullary  matter,  which  passes  from   one  hemisphere  to  the 
other  through  the  anterior  margins  of  the  thalami  optici.     Its 
middle  part  is  rounded  and  free,  but  its  extremities  penetrate 
into  the  substance  of  the  anterior  inferior  portion  of  the  corpus 
striatum,  and  spreading  out  gradually,  describe  a  curve  with  its 
convexity  forwards,  which  terminates  on  each  side  in  the  Taenia 
Hippocampi  of  the  inferior  cornu  of  the  lateral  ventricle.     This 
fasciculus,  in  penetrating  the  corpus  striatum,  does  not  mix  with 
its  substance,  but,  in  the  early  part  of  its  course,  goes  in  a  canal 
formed  in  the  latter.     In  order  to  see  this  arrangement,  a  part 
of  the  corpus  striatum  must  be  removed.     The  anterior  commis- 
sure resembles  a  nerve  in  its  structure,  as  it  is  surrounded  by  a 
very  delicate  sheath,  and  is  divided  into  fasciculi  of  fibres.     It 
will  now  be  understood  that  three  commissures  are  found  in  the 
third  ventricle,  the  anterior  Commissure — the  posterior,  which  is 
just  in  front  of  the  Pineal  Gland,t  and  soft  Commissure,  being  a 
cineritious  adhesion  of  the  Thalami.  J 

Just  behind  and  below  the  anterior  commissure,  the  base  of 
the  infundibulum  opens  into  the  third  ventricle ;  this  place  is  the 
Iter  ad  Infundibulum.  At  the  posterior  extremity  of  the  third 
ventricle,  just  below  the  posterior  commissure,  which  has  been 
described  as  a  process  of  the  pineal  gland,  the  communication 
exists  with  the  fourth  ventricle.  This  passage  is  the  Aqueduct 


*  Meckel,  Manuel  D'Anutomie. 

f  See  Pineal  Gland.  *  See  Thalami. 


370  NERVOUS  SYSTEM. 

of  Sylvius,  and  leads  obliquely  downwards  and  backwards  under 
the  valve  of  the  brain. 

The  third  ventricle  communicates  freely  with  the  lateral  ven- 
tricle through  the  aperture  called  the  Foramen  of  Monro,  which 
is  situated  precisely  at  the  place  where  the  plexus  choroides  ter- 
minates; that  is  to  say,  under  the  anterior  crus  of  the  fornix. 
Doubts  have,  from  time  to  time,  been  suggested  in  regard  to  the 
natural  existence  of  this  communication ;  it  only  requires  a  mo- 
derate degree  of  accurate  observation  to  dispel  them :  they  have 
arisen,  probably,  from  the  aperture  being  shut  up  by  the  occa- 
sional adhesion  of  the  plexus  choroides  to  the  contiguous  surface 
of  the  brain. 

The  Fourth  Ventricle  (Ventriculus  Quartus,  Cerebelli)  has 
been,  in  a  great  degree,  described  in  the  account  of  the  neigh- 
bouring parts;  it  will,  therefore,  be  very  readily  understood  on 
the  present  occasion.  It  is  an  irregular  triangular  cavity,  the 
base  of  which  is  downwards.  It  is  bounded  in  front  by  the  tuber 
annulare,  and  the  medulla  oblongata,  behind  by  the  fundamental 
portion  of  the  cerebellum,  and  above  by  the  valve  of  the  brain 
and  the  tubercula  quadrigemina ;  it  is  under  the  latter  that  the 
communication  between  it  and  the  third  ventricle  is  found.  Its 
lateral  parietes  are  formed  by  the  medullary  prolongations  from 
the  cerebellum  to  the  tubercula  quadrigemina.  This  cavity,  as 
stated,  is  open  below,  when  that  portion  of  pia  mater  is  removed, 
which  passes  from  the  cerebellum  to  the  medulla  oblongata. 

From  what  has  now  been  said  of  the  connexion  of  the  pia 
mater  with  the  ventricles,  it  will  be  understood  that  as  their  sur- 
faces are  covered  by  pia  mater,  and  the  removal  of  it  exposes 
their  cavities,  they  are,  in  fact,  continuations  of  the  external  sur- 
face of  the  brain. 


SECT.  VI. — OF  THE  NERVES  OF  THE  ENCEPHALON.* 

These  nerves  are  designated  numerically,  from  before  back- 
wards, and,  also,  by  some  peculiarity  of  distribution  or  function. 

*  The  more  improved  observations  of  modern  anatomists  having1  pointed  out 
the  fallacy  of  considering  the  brain  as  the  source  of  the  spinal  marrow,  instead  of 


NERVES  OF  THE  ENCEPHALON.  S71 

The  Olfactory  Nerve  or  First  Part  (Nervus  Olfactorius,  Par 
Primum,)  is  situated  on  the  under  surface  of  the  anterior  lobes 
of  the  brain,  near  the  fissure  that  separates  the  hemispheres.  It 
goes  forwards  from  its  root,  and  also  converges  gradually  to- 
wards its  fellow,  so  as  to  reach  the  cribriform  plate  of  the 
ethmoid  bone,  through  the  perforations  of  which  it  passes  out. 
In  its  course,  it  is  lodged  in  a  small  furrow,  by  which  pressure 
upon  it  is  prevented. 

This  nerve  arises  by  three  medullary  fasciculi,  or  roots,  from 
the  basis  of  the  brain  at  the  corpus  striatum,  in  the  fissure  of 
Sylvius,  where  the  anterior  and  middle  lobes  join  each  other : 
these  roots  are  from  eight  to  twelve  lines  on  the  outer  side  of 
the  infundibulum.  The  roots  are  placed,  in  regard  to  each  other, 
diverging;  one  is  within,  another  in  the  middle,  and  the  third 
external.  The  external  root  is  the  longest,  and  arises  from  the 
extreme  poslerior  margin  of  the  anterior  lobe  by  its  last  convo- 
lution. It  has  a  curved  course  from  without  inwards,  the  con- 
cavity of  which  is  forwards,  and  the  convexity  backwards.  The 
internal  root  is  concealed  by  the  chiasm  of  the  optic  nerves,  and 
arises  from  the  adjacent  surface  of  the  anterior  lobe.  The  middle 
root  comes  from  the  posterior  margin  of  the  anterior  lobe  by  the 
cribriform  surface,  which  is  between  the  other  two  roots.  These 
origins  unite  to  form  a  single  prismatic  cord,  which  increases  in 
size  as  it  advances  forwards,  and  consists  of  medullary  and  ci- 
neritious  longitudinal  fibres  mixed  together. 

The.  anterior  extremity  of  the  olfactory  nerve  is  swollen 
out  into  what  is  called  the  Bulb,  (Bulbus,)  and  sends  from  its 
under  surface  filaments,  which,  surrounding  themselves  with  a 
tunic  from  the  dura  mater,  penetrate  into  the  nose,  and  spread 
themselves  on  the  Schneiderian  membrane.  In  its  whole 
length  it  is  exceedingly  soft  and  pulpy,  till  it  gets  out  of  the 
cranium. 

The  Optic  Nerve  or  Second  Pair  (Nervus  Oplicus,  Par  Se- 

the  reverse;  it  follows,  that  the  proper  order  of  describing  the  nerves  of  the  en- 
cephalon,  is  successively  from  the  spinal  marrow.  I  had  adopted  this  plan,  for- 
merly, but  certain  considerations  of  facility  in  study,  have  induced  me  to  abandon 
it  after  some  years  of  experience. 


372  NERVOUS  SYSTEM. 

cundum)  is  about  the  same  size  with  the  trigeminus.  It  arises 
by  a  broad  flattened  root,  one  portion  of  which  comes  from  the 
posterior  end  of  the  thalamus  opticus,  and  another  from  the 
testis  through  the  means  of  a  medullary  band  that  passes  from 
the  latter  towards  the  thalamus  of  the  same  side.  From  this 
point  the  optic  nerve  winds  forwards  under  the  cms  cerebri, 
adhering  to  it,  and  inclining  inwards  towards  its  fellow.  Its 
adhesion  to  the  crus  is  considered  by  many  anatomists  as  an- 
other of  its  origins. 

The  Optic  Nerve,  having  reached  the  under  anterior  part 
of  the  third  ventricle,  adheres  so  closely  to  its  fellow  that  the 
two  seem  fused  together,  in  such  a  way  that  there  is  no  line  of 
separation  between  them.  This  junction  receives,  above,  from 
the  third  ventricle,  some  medullary  filaments,  which  Meckel 
feels  authorized  to  consider  as  another  origin.  The  junction 
presents  the  form  of  the  letter  X,  and  is  called  the  chiasm  or 
crossing  of  the  optic  nerves.  The  most  distinguished  anato- 
mists, however,  have  laboured  in  vain  to  settle  the  question  of 
the  mode  of  junction;  some  believing  that  there  was  only  a  la- 
teral union,  others  that  the  nerve  of  one  side  crossed  over  to 
the  other  side,  and  others,  again,  that  the  decussation  occurred 
only  with  some  of  the  fibres,  but  not  all.  Observations,  in 
comparative  anatomy,  on  blindness,  and  indeed  on  every  con- 
ceived mode  of  elucidation,  have  been  resorted  to  without 
producing  a  solution  of  the  problem;  but  the  discussion  of 
their  merits  would  require  too  much  space  for  the  present 
work. 

The  Optic  Nerves  as  they  approach  their  chiasm  become 
more  cylindrical,  and,  continuing  so  afterwards,  penetrate  into 
the  orbits  through  the  foramina  optica.  It  is  only  in  front  of 
their  junction  that  they  are  invested  by  a  neurileme;  which, 
having  considerable  firmness,  penetrates  into  their  interior,  and 
divides  them  into  distinct  canals. 

The  Nervus  Motor  Oculi,  or  Third  Pair  (Par  Tertium,) 
arises  from  the  internal  face  of  the  crus  cerebri,  about  two  lines 
in  advance  of  the  anterior  margin  of  the  tuber  annulare.  Its 
roots  come,  in  great  part,  from  the  cineritious  matter  which  is 
found  on  the  surface  of  the  crus,  and  may  be  traced  for  some 


NERVES  OF  THE  ENCEPHALON.  373 

Distance  upwards  and  backwards  along  the  parietes  of  the  third 
ventricle.  The  nerves  of  the  opposite  sides  are  in  contact  for 
some  distance  by  the  internal  faces  of  their  roots,  but  do  not 
adhere. 

The  Nervus  Motor  Oculi  proceeds  from  its  origin  towards 
the  external  margin  of  the  cavernous  sinus,  and,  penetrating  into 
the  orbit  through  the  sphenoidal  foramen,  it  is  distributed  to 
most  of  the  muscles  of  the  eye-ball. 

The  Pathetic  Nerve,  or  Fourth  Pair  (Nervus  Palheticus, 
Par  Cerebrale  Quartum,)  is  the  smallest  which  comes  from 
the  encephalon,  and  is  not  larger  than  a  sewing  thread.  It 
arises  by  two  filaments,  or  roots,  from  the  upper  anterior  face 
of  the  valve  of  the  brain,  just  below  the  testes.  This  origin  is 
soft,  and  easily  broken,  from  the  want  of  a  neurileme;  but  the 
latter  is  soon  afterwards  furnished. 

The  Nervus  Patheticus  appears  on  the  base  of  the  brain,  be- 
tween the  cerebellum  and  the  posterior  lobes  of  the  cerebrum,  at 
the  external  margin  of  the ''tuber  annulare.  It  then  goes  for 
some  distance  along  the  margin  of  the  tentorium  till  it  comes 
near  the  posterior  clinoid  process :  it  then  penetrates  into  a  ca- 
nal of  the  dura  mater,  and  reaches  the  orbit  of  the  eye  through 
the  sphenoidal  foramen,  to  be  distributed  on  the  superior  oblique 
muscle. 

The  Nervus  Trigeminus,  or  Fifth  Pair,  also  called  Trifacial, 
(Par  Quintum)  is  one  of  the  largest  among  those  that  proceed 
from  the  basis  of  the  brain,  and  emerges  from  the  side  of  the 
pons  varolii,  just  where  it  is  continuous  with  the  crus  cerebelli. 
It  is  composed  of  three  roots :  an  anterior,  a  posterior,  and  a  mid- 
dle ;*  of  which  the  latter  is  much  the  largest. 

The  middle  root  is  about  a  line  and  a  half  in  breadth,  and  has 
ti  passage  made  for  it  by  the  very  obvious  splitting  of  the  super- 
ficial fibres  of  the  pons  varolii.  It  is  composed  of  thirty  or  forty 
fasciculi,  which  are  divisible  into  a  hundred  or  more  fibres. 
These  fasciculi  may  be  traced  into  the  substance  of  the  tuber 

*  Santorini,  Observ.  Anat.  Venitia,  1724.  Soemmering1,  de  Corp.  Hum.  Fab- 
fcica,  torn.  iv.  Gall  and  Spurzhelra,  Anat.  du  Cerv. 

VOL.  II.— 48 


374  NERVOUS  SYSTEM. 

annulare,  (but  intersected  by  the  transverse  fibres  of  the  latter,) 
in  the  direction  of  the  fourth  ventricle.  When  they  have  come 
near  the  latter,  they  may  be  traced  thence  into  the  medulla  ob- 
longata,  towards  the  fissure  that  exists  between  the  corpus  oli- 
vare  and  restiforme.  It  is  at  this  point,  that  the  greater  num- 
ber of  the  fibres  arise ;  some  from  the  corpus  olivare,  and  others 
from  the  fissure. 

The  commencement  of  this  root  is  pulpy  and  destitute  of  fibres, 
and  is  surrounded  by  grayish  substance;  but  when  it  has  ad- 
vanced into  the  polls,  it  is  surrounded  by  a  fine  membrane,  and 
is  very  evidently  fibrous.  There  is  a  successive  increase  in  its 
size,  from  its  commencement  till  it  -is  ready  to  emerge  from  the 
pons,  when  it  becomes  somewhat  contracted,  and  immediately 
afterwards  increases  again  considerably  in  size.  It  then  enters 
a  canal  of  the  dura  mater  at  the  fore  part  of  the  petrous  por- 
tion of  the  temporal  bone,  and  just  behind  the  cavernous  sinus. 
This  canal  sets  but  loosely  about  it  at  first,  but  afterwards  it  ad- 
heres to  the  surface  of  the  nerve. 

The  middle  root  of  the  nervus  trigeminus,  in  the  upper  part 
of  the  canal  of  the  dura  mater,  preserves  its  fasciculated  ap- 
pearance, and  many  small  filaments  are  interchanged  between 
the  fasciculi,  so  as  to  make  a  complex  net-work.  But,  at  the 
lower  part  of  this  canal,  it  is  converted  into  a  ganglion  of  a 
semi-lunar  shape,  with  its  concavity  upwards,  being  about  six 
or  eight  lines  in  length,  and  one  and  a  half  in  breadth.  This 
body,  called  the  Ganglion  of  Gasser,  (Ganglion  Semi-lunare, 
Plexus  Gangliformis,}  is  compact,  and  has  its  fibres  very  much 
matted  above,  but  below  they  assemble  into  larger  and  more 
distinct  fasciculi,  which  are  afterwards  arranged  into  three  prin- 
cipal trunks,  departing  from  the  cranium  through  different  fora- 
mina ;  to  wit,  through  the  sphenoidal  foramen,  the  foramen  ro- 
tundum,  and  the  foramen  ovale. 

J.  F.  Meckel  asserts  that  the  filaments  of  the  plexus  above  the 
ganglion,  for  the  most  part  terminate  in  a  gutter  formed  in  the 
superior  margin  of  the  ganglion,  and  that  there  are  but  very  few 
of  them  which  can  be  traced  into  the  trunks  below.  The  trunks 
below,  consequently,  arise  from  the  circumference  of  the  gan- 
glion. 

The  two  smaller  roots  of  the  nervus  trigeminus  proceed  out 


NERVES  OF  THE  ENCEPHALON.  375 

of  the  tuber  annulare  at  different  points,  from  that  of  the  large 
root,  and  each  one  has  its  appropriate  fissure  for  that  purpose. 
One,  from  its  situation,  is  called  Anterior,  and  the  other  Poste- 
rior. Each  may  be  traced  into  the  posterior  cord  of  the  me- 
dulla oblongata,  but  not  so  far  as  the  large  middle  root,  and  is 
formed  by  several  fasciculi  of  medullary  fibres.  The  anterior 
and  the  posterior  roots,  after  going  separately  for  six  or  eight 
lines,  unite  to  form  a  single  cord.  This  cord  does  not  merge  it- 
self in  the  semi-lunar  ganglion,  but  continues  distinct  from,  it,* 
with  the  exception  of  sending  off  to  it  a  few  fasciculi;  it  after- 
wards gets  from  the  cranium  through  the  foramen  rotundum, 
and  is  distributed  to  some  of  the  muscles  of  mastication,  as  the 
the  temporal  and  buccinator. 

The  general  distribution  of  the  fifth  pair  of  nerves,  or  the  tri- 
geminus,  is  to  the  orbit,  to  the  face,  and  to  the  tongue. 

The  Motor  Oculi  Exiernm,  or  Sixth  Pair  of  Nerves  (Par  Sex- 
turn)  is  found  four  or  five  lines  distant  from  the  facial  nerve,  and 
at  its  internal  side*  It  arises  from  the  base  or  upper  extremity 
of  the  corpus  pyramidale,  under  the  posterior  margin  of  the  tuber 
annulare:  when  the  latter  is  broader  than  usual,  some  of  the 
fibres  seem  to  come  from  it;  but  the  appearance  is  deceptious, 
as  they  only  penetrate  it.  The  fibres  are  assembled  into  two 
roots,  of  which  the  internal  is  three  or  four  times  as  large  as  the 
other. 

These  roots,  before  they  penetrate  the  dura  mater,  most  com- 
monly unite  into  a  single  trunk,  which  goes  almost  directly  for- 
wards, and  is  enveloped  in  a  neurileme.  Passing  through  the 
cavernous  sinus,  it  gets  into  the  orbit  by  the  sphenoidal  foramen, 
and  is  spent  upon  the  abductor  oculi  muscle. 

The  Seventh  Pair  of  Nerves  is  composed  of  the  Facial  and 
the  Auditory. 

The  Facial  Nerve  (Nervus  Facialis,  Portio  Dura,  Septimi, 
Par  Septimum)  is  placed  in  front  of  and  above  the  auditory  nerve. 
It  arises  by  two  branches,  which  are  perfectly  distinct  from 

*  In  this  respect  the  fifth  pair  resembles  one  of  the  spinal  nerves. 


376  NERVOUS  SYSTEM. 

each  other,  and  differ  much  in  their  size.  The  larger  onc> 
which  is  placed  within  and  above  the  other,  arises  from  the  me- 
dulla oblongata  at  the  most  superior  part  of  the  corpus  resti- 
forme,  where  the  latter  joins  the  tuber  annulare.  The* origin  of 
the-  nerve  is  sometimes  overlapped  by  the  latter,  so  that  some 
few  of  its  fibres  appear  to  come  from  the  annular  protuberance, 
while  they  only  pass  through  it,  in  their  course  from  the  medul- 
la oblongata.  The  second  branch,  which  is  much  smaller  than 
the  other,  arises,  4>y  three  or  four  filaments,  from  that  portion  of 
the  medulla  oblongata  which  is  placed  between  the  first  branch 
and  the  auditory  nerve. 

The  two  branches  of  the  facial  nerve  are  kept  distinct  for  the 
distance  of  several  lines  before  they  unite.  Proceeding  outwards 
and  backwards,  they  reach  the  meatus  auditorius  interims,  and 
then  proceed,  as  a  single  cylindrical  trunk,  through  the  aqueduct 
of  Fallopius,  to  emerge  at  the  stylo-mastoid  foramen,  for  the 
purpose,  of  being  distributed  upon  the  muscles  and  skin  of  the 
head. 

The  Auditory  Nerve  (Nervus  Auditorius^  Acusticus,  Portio  Mol- 
lis  Septimi)  arises,  in  part,  from  the  medullary  striae  on  the  sur- 
face of  the  calamus  scriptorius,  and  partly  from  the  corpus  res- 
tiforme,  between  the  glosso-pharyngeal  nerve  and  the  tuber 
annulare.  At  its.  origin  it  is  so  extremely  soft  as  not  to  bear 
handling,  and  is  too  pulpy  to  present  the  appearance  of  fibres ; 
but,  becoming  more  distant  from  the  medulla  oblongata,  it  is 
harder  and  more  fibrous. 

This  nerve  is  impressed  on  its  internal  face  by  a  longitudinal 
furrow  for  the  reception  of  the  facial  nerve.  It  passes  obliquely 
forwards  and  outwards  beneath  the  crus  cerebelli,  and  penetrates 
into  the  meatus  auditorius  internus.  It  adheres  somewhat  near 
its  root  to  the  under  anterior  margin  of  the  cerebellum,  just  be- 
hind the  crus  of  the  latter :  the  circumstance  is  considered  by  J. 
F.  Meckel,  as  a  proof  of  its  having  there  another  origin,  where- 
by an  analogy  is  established  between  it  and  the  two  other  nerves 
of  the  senses;  to  wit,  the  optic  and  the  olfactory. 

The  distribution  of  this  nerve  is  confined  to  the  labyrinth  of 
the  ear. 


NERVES  OF  THE  ENCEPHALON.  377 

The  Eighth  Pair  of  Nerves  is  composed  of  the  Glosso-Pharynr 
geal,  the  Pneumogastric  and  the  Spinal  Accessory. 

The  Glosso-Pharyngeal  Nerve  (JVervus  Glosso-Pharyngeus,  of 
Eighth  Pair,)  arises  from  the  posterior  cord  of  the  medulla  ob- 
longata,  just  above,  and  somewhat  anterior  to  the  superior  fila- 
ments of  the  next  nerve,  with  which  it  is  very  closely  connected. 
Its  filaments,  which  are  five  or  six  in  number,  spring,  therefore, 
from  the  anterior  margin  of  the  corpus  restiforme,  or  from  the 
fissure  separating  it  from  the  corpus  olivare,  under  the  posterior 
margin  of  the  tuber  annulare.  , 

Its  filaments  soon  collect  into  a  round  cord,  and  anastomose, 
even  in  the  cavity  of  the  cranium,  by  a  considerable  branch 
with  the  pneumogastric.  It  runs  outwards  and  backwards  to 
the  foramen  lacerum  posterius,  and  goes  through  the  same  divi- 
sion of  it  that  the  pneumogastric  does,  but  in  its  own  canal  of 
the  dura  mater.  About  half  an  inch  from  this  canal  it  en- 
larges within  the  cranium,  into  a  small  oblong  ganglion  of  five 
or  six  lines  long,  which  extends  itself  as  far  as  the  foramen  lace- 
rum.* 

Its  general  distribution  is  to  the  tongue  and  to  the  pharynx, 
as  its  name  implies. 

The  Pneumogastric  Nerve  (Nervus  Pneumogaslricus  or  Vagus$ 
of  Eighth  Pair,)  arises  from  the  corpus  restiforme  of  the  medulla 
oblongata,  just  behind,  or  on  the  borders  of  the  fissure  separating 
it  from  the  corpus  olivare,  somewhat  above,  and  posterior  to  the 
highest  root  of  the  accessory  nerve.  It  commences  by  a  num- 
ber of  parallel  filaments,  varying  in  number  from  ten  to  fifteen, 
which  are  placed  very  near  each  other,  so  as  to  form  two  or 
three  flattened  fasciculi  of  half  an  inch  or  more  in  length.  The 
fasciculi  below  adhere  to  the  spinal  accessory,  and  those 
above  to  the  glosso-pharyngeal  nerve.  The  fasciculi,  finally, 
collect  into  a  single  flattened  cord  of  one  and  a  half  lines  in 
breadth. 

This  cord  goes  outwards  and  backwards  to  the  foramen  lace- 
rum  posterius,  and  gets  through  it  in  front  of  the  internal  jugular 

*  This  ganglion  is  described  by  Andersech  and  by  Huber,  but  its  existence  is 
questioned  by  Bichat. 


378  NERVOUS  SYSTEM. 

vein,  being  separated  from  the  latter  by  the  small  spine  which 
arises  from  the  pars  petrosa  of  the  temporal  bone.  It  passes 
through  its  own  canal  in  the  dura  mater,  being  thus  kept  distinct 
from  the  glosso-pharyngeal,  and  from  the  accessory  nerve,  and 
in  this  canal  the  fasciculi  which  form  it  are  collected  into  a  single 
cylindrical  trunk.  After  getting  through  the  canal  it  then  ad- 
heres by  a  close,  strong,  cellular  substance,  to  the  glosso-pharyn- 
geal and  to  the  accessory. 

The  general  plan  of  distribution  of  the  pneumogastric  nerve 
is,  as  its  name  implies,  to  the  organs  of  respiration,  and  to  the 
stomach. 

The  Accessory  Nerve  (Nervus  Accessories,  of  Eighth  Pair,) 
arises  from  the  posterior  fasciculus  of  the  medulla  oblongata,  just 
behind  the  nervus  hypoglossus,  and  also  from  the  posterior  fasci- 
culus of  the  medulla  spinalis,  sometimes  as  low  down  as  the 
seventh  cervical  nerve.  There  are  six  or  seven  roots  front 
the  medulla  spinalis,  and  about  three  or  four  from  the  medul- 
la oblongata:  the  former  are  single,  and  run,  successively, 
into  the  same  trunk ;  but  the  latter  are  each  composed  of  two 
branches,  consisting  respectively  of  twro  filaments.  These  roots 
are,  successively,  larger  and  longer,  as  they  ascend  to  join  the 
common  trunk.  The  latter  goes  up  between  the  posterior  fasci- 
culi of  spinal  nerves  and  the  ligamentum  denticulatum,  and  gets 
into  the  cavity  of  the  cranium,  behind  the  vertebral  artery, 
through  the  foramen  magnum  occipitis. 

This  nerve  varies  in  respect  to  the  number  of  its  roots,  and 
the  mode  of  their  origin.  In  all  cases,  the  trunk,  thus  formed, 
passes  from  the  cranium  through  the  foramen  lacerum  posterius, 
traversing  there  the  dura  mater,  either  in  a  sheath  common  to  it 
and  to  the  pneumo-gastric  nerve,  or  in  its  own  particular  open- 
ing behind  that  of  the  latter. 

Its  general  distribution  is  to  the  muscles  and  to  the  integu- 
ments of  the  neck. 

The  Hypoglossal  Nerve,  (Nervus  Hypoglossus,  or  Ninth  Pair,) 
arises  from  the  medulla  oblongata,  by  several  fasciculi  placed 
one  above  the  other.  The  roots  of  thesejasciculi  [spring  from 
the  fissure  which  separates  the^corpus  pyramidale  from  the  cor- 


ARTERIES  OF  THE  BRAIN.  379 

pus  olivare.  The  fasciculi  are  from  four  to  eight  in  number,  be- 
ing subject  to  vary  in  different  individuals.  They  unite  into  two 
or  three  trunks,  which  coalesce  into  one,  after  penetrating  the 
dura  mater  by  distinct  openings ;  and  then  proceed  through  the 
anterior  condyloid  foramen  of  the  occipital  bone. 

The  general  distribution  of  this  nerve  is  to  the  muscles  of  the 
tongue. 


SECT.  VII.-— Of  THE  ARTERIES  OP  THE  BRAIN". 

The  arteries  of  the  brain,  or  pia  mater,  are  derived  from  the 
two  internal  carotids,  and  from  the  two  vertebrals. 

The  Internal  Carotid  Artery  (Carotis  Inlerna)  gets  into  the  ca- 
vity of  the  cranium  through  the  carotid  canal  of  the  temporal 
bone,  conforming  itself  of  course  to  the  curvature  of  this  canal, 
and  is  brought  by  it  to  the  posterior  part  of  the  body  of  the 
sphenoidal  bone.  In  escaping  from  the  petrous  bone  it  has  to 
ascend,  and  also  to  advance  somewhat,  by  which  it  is  brought 
to  the  posterior  part  of  the  sella  turcica.  From  this  point  it 
goes  horizontally  forwards  through  the  cavernous  sinus;  and 
reaching  its  fore  part,  it  then  ascends  again,  and  towards  the  fis* 
sure  of  Sylvius.  While  in  the  carotid  canal,  it  gives  a  small 
branch  to  the  tympanum  of  the  ear,  and  as  it  lies  on  the  side  of 
the  sella  turcica  it  gives  off  the  anterior  and  the  posterior  arte- 
ries of  the  cavernous  sinus.  When  it  reaches  the  anterior  cli- 
noid  process  it  sends  off  a  large  branch  through  the  optic  fora- 
men to  the  parts  contained  within  the  orbit  of  the  eye.  This 
branch  is  the  ophthalmic  artery,  and  what  remains  of  the  inter- 
nal carotid  is  then  distributed  to  the  brain  after  the  following 
order : — 

There  are,  first  of  all,  some  small  branches  sent  to  the  adja* 
cent  parts;  as  the  pituitary  gland,  the  infundibulum,  and  the 
lower  part  of  the  third  ventricle. 

The  Arteria  Communicans  Posterior  is  directed  backwards 
and  inwards,  and  runs  into  the  corresponding  trunk*  of  the  basi* 


380  NERVOUS  SYSTEM. 

lar  artery  called  the  posterior  cerebral.  There  are  some  varie- 
ties in  regard  to  the  size  and  precise  point  of  origin  of  this  trunk, 
which  it  would  be  needless  to  mention  particularly.  Besides  the 
important  anastomosis  formed  by  it,  it  detaches  several  ramus- 
cles  to  the  adjacent  parts  of  the  pia  mater. 

The  Arteria  Choroidea  is  the  next  branch  from  the  internal 
carotid.  It  goes  outwards  and  backwards,  and  after  detaching 
some  minor  branches,  it  penetrates  into  the  inferior  cornu  of  the 
lateral  ventricle,  by  the  side  of  the  Pons  Varolii,  and  expends  it- 
self in  ramifications  upon  the  plexus  choroides. 

The  Arteria  Callosa,  or  Anterior  Cerebri,  is  detached  from 
the  internal  carotid,  opposite  the  last.  It  advances  in  front  of 
the  union  of  the  optic  nerves,  converging  rapidly  at  the  same 
time  towards  its  fellow.  Just  before  the  chiasm  of  the  optic 
nerves,  a  transverse  branch  passes  between  it  and  its  fellow. 
This  branch,  the  Arteria  Communicans  Anterior,  is  of  variable 
length  and  size  in  different  subjects,  being  sometimes  a  line,  and 
on  other  occasions  three  or  four  lines  long. 

The  arteria  callosa  then  keeps  near  its  fellow  on  the  under 
surface  of  the  hemisphere,  giving  out  small  branches ;  and  having 
got  on  a  line  with  the  anterior  margin  of  the  corpus  callosum,  it 
ascends  on  the  flat  side  of  the  hemisphere;  and  divides  into 
anterior  and  into  posterior  twigs.  The  former  supply  the  fore 
flat  part  of  the  hemisphere ;  the  latter  the  corpus  callosum  and 
"the  adjacent  surface  of  the  brain.  These  several  branches  of 
the  arteria  anterior  reach  as  far  as  the  upper  convex  surface  of 
-the  brain,  and  there  anastomose  with  other  arteries. 

The  Internal  Carotid  may  now  be  considered  to  have  lost  its 
name,  and  the  trunk  is  continued  as  Arteria  Cerebri  Media.  It 
is  directed  outwards,  and  engages  in  the  fissure  of  Sylvius; 
while  there  it  detaches  a  great  number  of  branches  to  the  ad- 
joining surfaces  of  the  anterior  and  of  the  middle  lobe.  Some 
of  these  branches  are  of  considerable  magnitude,  and  winding 
along  the  convolutions  of  the  brain,  they  at  length  ascend  to  the 
upper  surface  of  the  hemisphere,  and  anastomose  with  the 
branches  of  the  anterior  and  of  the  posterior  cerebral  artery. 

The  Vertebral  Artery  (Jlrteria  Vertebralis)  is  a  branch  of 


ARTERIES  OF  TflE  BRAIN.  381 

the  subclavian.  In  order  to  reach  the  cavity  of  the  cranium  it 
has  to  traverse  the  foramina  of  the  transverse  processes  of  the 
six  upper  vertebrae  of  the  neck.  It  ascends  in  a  straight  line 
till  it  reaches  the  second  vertebra,  but  there,  in  order  to  pass 
through  the  transverse  process,  it  takes  a  direction  upwards  and 
outwards.  It  then  ascends  vertically  again  till  it  has  passed 
through  the  transverse  process  of  the  first  vertebra.  After  which 
it  takes  a  horizontal  course,  winding  around  the  posterior  face 
of  the  upper  oblique  process  of  the  same  vertebra,  in  a  depres- 
sion for  the  purpose,  and  having  reached  the  internal  extremi- 
ty of  this  process,  it  ascends  upwards  and  inwards  through  the 
occipital  foramen  into  the  cavity  of  the  cranium:  perforating 
the  dura  mater  just  above  the  condyle  of  the  occipital  bone. 
Having  got  into  the  cranium,  it  is  first  on  the  side  and  the/i  on 
the  under  surface  of  the  medulla  oblongata,  and  continues  to  ap- 
proach its  fellow  till  it  reaches  the  posterior  margin  of  the  tu- 
ber annulare.  At  this  point  the  two  vertebral  arteries  coalesce, 
and  from  their  union  results  the  basilar  artery. 

The  vertebral  artery  in  this  course,  from  its  origin  to  its  ter- 
mination, detaches  several  arterioles  to  the  heads  of  the  adjoin- 
ing muscles,  to  the  membranes  of  the  spinal  marrow,  and  to  the 
nerves  as  they  come  out  of  the  intervertebral  foramina:  they 
are  generally  too  small  and  irregular  to  deserve  a  special  de- 
scription. At  its  upper  extremity,  however,  it  sends  off  three 
branches  of  some  consequence:  the  Spinalis  Posterior,  the  Spi- 
nalis  Anterior;*  and  the  Inferior  Cerebelli. 

The  Arteria  Inferior  Cerebelli  divides  shortly  after  its  ori- 
gin, or  otherwise  is  double  from  the  beginning.  The  most  pos- 
terior trunk  is  distributed  about  the  bottom  of  the  fourth  ven- 
tricle, on  the  fundamental  portion  of  the  cerebellum,  and  the 
contiguous  faces  of  the  two  hemispheres  or  lobes  of  the  latter. 
The  other  trunk  of  this  artery  is  distributed  on  the  under  surface 
of  the  cerebellum. 

The  Basilar  Artery  (firteria  Basilaris)  is  on  the  middle  line 
of  the  tuber  annulare,  and  extends  from  its  posterior  to  its  an- 
terior margin.  In  this  course  it  detaches  some  arterioles  to  the 

*  See  Arteries  of  Medulla  Spinalis. 
VOL.  IL— 49 


3S2  NERVOUS  SYSTEM. 

tuber;  others  to  the  meatus  auditorius  internus,  (Jlrterise  Jludi- 
tivae  LiternsBj]  which  are  spent  upon  the  labryinth,  and  anas- 
tomose with  twigs  from  the  internal  and  external  carotids.  At 
its  anterior  extremity  it  detaches  on  each  side  two  considerable 
trunks;  first  the  superior  artery  of  the  .cerebellum,  and  imme- 
diately afterwards  the  posterior  artery  of  the  cerebrum. 

The  Arteria  Superior  Cerebelli  goes  outwardly  from  its  ori- 
gin just  behind  the  anterior  edge  of  the  tuber  annulare,  until  it 
gains  the  front  margin  of  the  cerebellum.  It  then  divides  into 
several  branches,  some  of  which  are  distributed  on  the  upper 
surface  of  the  cerebellum  and  run  to  its  posterior  margin,  where 
they  anastomose  with  the  branches  of  the  arteria  inferior:  others 
are  spent  upon  the  substance  of  the  cerebellum  near  its  anterior 
edge. 

The  Posterior  Artery  of  the  Cerebrum,  {Jlrleria  Cerebri 
Posterior^)  one  on  each  side,  is  the  termination  of  the  basilar 
artery.  It  proceeds  abruptly  outwards,  and  has  gone  but  a  few 
lines  when  it  receives  the  arteria  communicans  posterior  of  the 
internal  carotid.  It  then  continues  outwardly  parallel  with  the 
anterior  margin  of  the  tuber  annulare,  and  near  it  crosses  the 
crus  cerebri,  and  is  then  distributed,  on  the  inferior  and  on  the 
posterior  part  of  the  hemisphere  and  of  the  corpus  callosum. 
As  mentioned,  its  branches  anastomose  with  those  of  the  ante- 
rior and  of  the  middle  arteries  of  the  cerebrum. 

It  will  now  be  understood,  that  an  arterial  circle  or  link  en- 
'closes  the  chiasm  of  the  optic  nerves  and  the  corpora  albicantia. 
The  fore  and  lateral  parts  of  the  circle  are  formed  by  the  inter- 
nal carotids  and  their  branches;  while  the  hind  part  is  formed 
by  the  Basilar  Artery  and  its  bifurcation.  This  is  the  circle  of 
Willis,  and  establishes  a  very  free  communication  between  the 
vessels  of  the  two  sides  of  the  brain. 


The~veins  of  the'  Brainwave  been  sufficiently  alluded  to  in 
the  account  of  the  Pia  Mater,  and  of  the  sinuses  of  the  Dura 
Mater, 


BOOK  IX. 


PART  III. 

Se?ises. 

To  the  peripheral  portion  of  the  nervous  system,  belong  all 
the  nerves  which  are  sent  off  from  the  Medulla  Spinalis  and 
Encephalon,  as  well  as  the,  Sympathetic.  Some  of  these  nerves 
have  a  special  apparatus  attached  to  their  external  extremities, 
for  the  purpose  of  augmenting  and  facilitating  their  appropriate 
powers  of  sensation;  of  this  class  are  the  Olfactory,  the  Optic, 
and  the  Auditory.  Others  of  them,  as  the  nerves  of  the  tongue 
and  of  the  skin,  though  they  are  the  means  of  special  sensations, 
yet  the  apparatus  upon  which  they  are  spread  is  applied  to 
many  purposes,  more  striking  and  useful,  than  that  of  indicating 
the  presence  of  surrounding  bodies.  And,  lastly,  the  remaining 
nerves,  being  by  far  the  most  numerous  and  large,  are  distri- 
buted to  the  muscles  and  to  the  viscera. 


CHAPTER  I. 


OF  THE  ORGAN  OF  SMELLING,  OR  THE  NOSE. 

THE  two  succeeding  senses  are  so  insulated  in  their  offices, 
that  there  can  be  no  doubt  of  the  propriety  of  considering  them 


384  NERVOUS  SYSTEM. 

as  belonging  to  the  peripheral  portion  of  the  nervous  system: 
but  the  nose  being,  in  the  human  subject,  though  not  in  all 
animals,  associated  with  the  function  of  respiration,  its  allo- 
cation is  less  exceptionable.  Without  detailing  the  considera- 
tions which  have  induced  me  to  put  its  description  under  this 
head,  I  will  only  mention  that  I  have  been  principally  actuated 
by  its  office  of  smelling  and  by  its  position. 

In  common  language,  the  term  nose  is  applied  to  the  part  of 
the  organ  of  smelling  which  manifests  itself  externally;  but  a 
very  extensive  cavity  of  the  same  vertical  diameter,  and  divided 
into  two  equal  compartments,  exists  behind  it,  the  form  of 
which  has  been  described  in  the  account  of  the  bones  of  the 
nose.  This  cavity  extends  from  the  bottom  of  the  cranium  to 
the  roof  of  the  mouth,  and  backwards  to  within  an  inch  and  a 
quarter  of  the  vertebra  of  the  neck.  The  nose,  externally,  is 
generally  pyramidal,  and  has  its  base  below;  what  is  technically 
called  the  root  of  the  nose  is  the  part  contiguous  to  the  fore- 
head. The  base,  on  each  side,  is  marked  from  the  cheek,  by 
a  semicircular  depression;  which  becoming  more  and  more 
shallow  at  its  upper  extremity,  and  increasing  its  breadth,  is 
insensibly  lost  upon  the  side  and  point  of  the  nose.  The  ala 
nasi  is  the  swell  of  the  posterior  part  of  the  base,  being  bounded 
behind  by  the  depression.  The  base  of  the  nose  offers  on  each 
side  an  oblong  oval  orifice,  looking  downwards  and  having  its 
long  diameter  forwards  and  slightly  inwards.  These  openings 
are  commonly  about  two  lines  below  the  floor  of  the  nose,  but 
there  is  a  diversity  in  this  respect. 

The  Nasus  Cartilagineus,  or  the  cartilaginous  portion  of  the 
nose,  is  placed  wholly  at  its  anterior  extremity,  and  serves  to 
elongate  the  cavity  in  that  direction.  It  presents  a  vertical 
cartilage,  which  is  in  continuation  of  the  bony  septum:  on 
each  side  of  this,  there  is  an  oval  cartilage,  and  behind  and 
below  the  latter,  several  distinct  and  small  pieces  of  cartilage, 
which  preserve  the  form  of  the  alae  nasi,  and,  in  fact,  constitute 
them. 

The  Vertical  Cartilage,  or  Cartilaginous  Septum  (Septum 
Cartilagineum)  is  placed  in  the  middle  line  of  the  nose,  and 


ORGAN  OF  SMELLING.  385 

has  its  anterior  angle  projecting  beyond  the  bony  orifice  of  the 
anterior  nares.  Occasionally,  from  a  faulty  conformation,  it 
inclines  more  to  one  side  than  to  the  other.  It  adheres,  by  its 
superior  margin,  to  the  nasal  lamella  of  the  ethmoid  and  to  the 
middle  nasal  suture,  and  behind  to  the  anterior  margin  of  the  t 
vomer.  The  inferior  margin  is  free  in  the  greater  part  of  its 
extent,  but  adheres  behind  to  the  suture  between  the  maxillary 
bones.  The  anterior  margin  sends  out,  on  each  side,  a  trian- 
gular plate,  the  upper  edge  of  which  adheres  to  the  inferior 
margin  of  the  nasal  bone,  and  of  the  nasal  process  of  the  upper 
maxillary.  These  plates  form  the  upper  part  of  the  cartilagi- 
nous nose,  and  from  their  ligamentous  attachment  to  the  bones, 
admit  of  a  slight  motion  from  side  to  side. 

The  Oval  Cartilages,  one  on  each  side,  are  a  species  of  ellip- 
tical ring,  but  deficient  or  open  at  their  posterior  end.  The 
external  side  of  the  ring,  is  an  oblong  oval  plate,  which  is  di- 
rected upwards  and  backwards.  The  internal  half  of  the  ring 
is  much  narrower,  and  proceeds  backwards  from  the  preceding 
part  at  a  very  acute  angle:  its  superior  margin  is  in  contact 
with  the  septum;  its  inferior  margin  reaches  below  the  latter, 
and  its  anterior  extremity  is  in  contact  with  its  fellow,  owing 
to  the  cartilaginous  septum  not  reaching  so  far  forwards.  The 
place  of  contact  of  the  two  oval  cartilages  to  each  other,  forms 
the  tip  of  the  nose  and  the  columna  nasi,  and  gives  the  apparent 
thickness,  before  dissection,  to  the  lower  part  of  the  septum 
narium. 

The  Alse  Nasi,  or  the  convexities  on  each  side  of  the  base 
of  the  nose,  it  has  been  said,  owe  their  shape  to  the  presence 
of  several  small  pieces  of  cartilage,  whose  form,  size,  and  num- 
ber are  too  variable  to  admit  of  a  standard  description:  occasion- 
ally they  are  all  collected  into  but  one  cartilage.  They  serve 
a  similar  purpose  with  the  oval  cartilage,  and  with  it  are  the 
means  by  which  the  orifice  of  the  nose  is  kept  patulous.  They 
are  deposited  in,  and  held  together  by  a  ligamentous  membrane. 
This  membrane  attaches  them  to  the  lateral  margin  of  the  an- 
terior bony  nares,  and  also  unites  the  upper  edge  of  the  ex- 
ternal plate  of  the  oval  cartilage  to  the  inferior  margin  of  the 
triangular  plate  of  the  cartilaginous  septum.  It  is  the  length 
and  looseness  of  this  ligament  which  permits  such  free  motion 


386  NERVOUS  SYSTEM. 

to  the  end  of  the  nose.  In  addition  there  exists  a  small  liga- 
ment described  by  Caldani,  which  goes  from  the  posterior  end 
of  the  columna  nasi  to  the  anterior  inferior  margin  of  the  bony 
nares. 

» 

The  skin  which  covers  the  upper  half  of  the  nose  is  loosely 
attached,  by  cellular  substance,  to  the  subjacent  parts,  but  it 
adheres  very  closely  to  the  surface  of  the  cartilaginous  and  li- 
gamentous  structure,  and  is  abundantly  furnished  with  seba- 
ceous glands  and  follicles.  The  exterior  orifices  of  the  latter 
are  apparent,  and  are  often  filled  with  their  appropriate  fluid  in 
an  inspissated  state,  which,  when  forced  out  by  pressure,  as- 
sumes the  form  of  small  worms,  the  blackness  of  the  end  of 
which  is  only  dirt. 

There  are  several  muscles  destined  to  move  the  cartilaginous 
structure  of  the  nose,  which  have  been  described  among  those 
belonging  to  the  face. 

The  Levator  Labii  Superioris  Alasque  Nasi,  which  lies  upon 
the  side  of  the  nose  and  comes  from  the  superior  part  of  the 
nasal  process  and  body  of  the  upper  maxillary  bone,  is,  besides 
its  insertion  into  the  upper  lip,  connected  with  the  ala  nasi,  and 
will  draw  the  latter  upwards. 

The  Compressor  Naris,  arising  from  the  ala  nasi  by  a  small 
pointed  beginning,  is  spread  out  upon  the  upper  edge  of  the 
cartilage  and  upon  the  triangular  plate,  so  as  to  cover  it,  and  is 
inserted  into  its  fellow  on  the  middle  line. 

The  Depressor  Labii  Superioris  Ala3que  Nasi,  by  arising  from 
the  roots  of  the  alveolar  processes  of  the  incisor  and  canine 
teeth  of  the  upper  jaw,  and  going  to  be  inserted  into  the  ala 
nasi,  as  well  as  into  the  upper  lip,  will  draw  the  ala  nasi  down- 
wards. 

The  Nasalis  Labii  Superioris,  or  Depressor  Narium,  which 
is  the  pointed  production  from  the  orbicularis  oris,  going  into 
the  columna  nasi,  will  draw  the  latter  downwards  and  back- 
wards. 

The  Mucous  Membrane  of  the  Nose  (Membrana  Pituitaria, 
Schneideriana)  lines^the  whole  of  each  side  of  the  nose,  pene- 
trates into  the  several  sinuses  and  cavities  communicating  with 


ORGAN  OF  SMELLING.  387 

ijt,  and  is  continuous,  at  the  orifice  of  the  nostrils,  with  the 
skin,  and  at  the  posterior  nares,  with  the  mucous  membrane  of 
the  pharynx. 

It  is  not  of  essential  importance  to  trace  its  course  from  any 
particular  point,  but  for  the  sake  of  perspicuity,  we  may  begin 
at  the  floor  of  the  nostril,  which  it  covers  in  a  smooth  even 
manner.  From  this  it  ascends  on  the  septum  narium,  which  it 
covers  also  smoothly  without  forming  any  fold  or  duplicature, 
and  adheres  so  loosely  that  it  may  be  detached  with  great  fa- 
cility. Behind,  it  covers  the  body  of  the  sphenoid  bone,  and 
lines  its  cell;  in  front,  it  covers  smoothly  the  os  nasi  and  nasal 
process  of  the  upper  maxillary  bone,  and  also  the  cartilaginous 
nose.  Above,  it  is  reflected  upon  the  cribriform  plate  of  the 
ethmoid  bone,  and  blocks  up  all  its  foramina.  At  this  point, 
the  olfactory  nerves  seem  to  terminate  on  its  surface  and  ad- 
here very  closely  to  it. 

From  the  cribriform  plate,  the  Schneiderian  membrane  passes 
to  the  cellular  part  of  the  ethmoid,  and  covers  smoothly  its  an- 
terior half.     But  behind,  as  it  passes  over  the  upper  spongy 
bone,  a  pendulous  duplicature  is  formed  along  its  inferior  mar- 
gin, and  is  continued  beyond  the  bone,  backwards  as  far  as  the 
spheno-palatine  foramen.     It  then  lines  the  upper  meatus  and 
the  posterior  cells  of  the  ethmoid,  and  is  extended  upon  the 
convex  surface  of  the  middle  spongy  bone.     At  the  inferior 
margin  of  the  latter,  it  forms  another  loose  and  somewhat  pen- 
dulous duplication,  which  does  not  go  beyond  the  posterior  ex- 
tremity of  the  bone.     The  membrane  is  then  reflected  into  the 
middle  meatus  of  the  nose,  and  penetrates  into  the  maxillary 
sinus  which  it  lines  completely.     The  orifice  through  which  it 
enters,  is  about  the  size  of  a  crow-quill;  is  variable  in  its  situa- 
tion, being  sometimes  in  the  middle  of  the  meatus,  sometimes 
more  forward,  and  on  other  occasions  higher  up  and  concealed 
by  irregularities,  in  the  conformation  of  the  ethmoid.    This  ori- 
fice, which  was  found  to  be  so  large  and  jagged  in  the  dried 
bone,  is  reduced  to  its  present  size  entirely  by  the  mode  of  re- 
flection of  the  mucous  membrane  over  its  margins.     In  front  of 
the  latter  orifice,  beneath  the  anterior  margin  of  the  middle  tur- 
feinated  bone,  the  rmicous  membrane  is  reflected  into  the  ante- 


388  NERVOUS  SYSTEM. 

rior  ethmoidal  cells  by  one  or  more  foramina,  and  through  the 
most  anterior  of  these  cells  into  the  frontal  sinus. 

From  the  middle  meatus,  this  membrane  passes  upon  the 
lower  turbinated  bone  so  as  to  cover  it,  and  also  to  form  a  loose 
duplication  along  its  inferior  margin;  it  then  lines  the  inferior 
meatus  of  the  nose,  and  is  continued  on  its  floor  into  the  part 
from  which  its  description  commenced.  Under  the  anterior 
part  of  the  inferior  spongy  bone,  this  membrane  is  continued 
into  the  lining  membrane  of  the  lachrymal  sac,  and  there  forms 
a  fold,  frequently  resembling  a  valve.  Along  the  posterior  mar- 
gin of  the  vomer,  the  membrane  of  the  nostril  is  continued  into 
the  corresponding  one  of  the  other  side,  whose  arrangement  is 
in  all  respects  the  same. 

The  pituitary  membrane,  in  its  structure  and  appearance,  re- 
sembles other  mucous  membranes;  its  colour,  however,  is  na- 
turally of  a  deeper  red.  It  consists  of  two  laminae,  which  can- 
not be  readily  separated:  the  one  next  to  the  cavity  of  the  nos- 
tril has  the  mucous  structure;  the  exterior  one  is  fibrous,  and 
resembles  the  periosteum  of  other  parts  of  the  body.  This 
composition  is  best  seen  on  the  part  belonging  to  the  septum 
narium. 

By  floating  the  pituitary  membrane  in  water  its  mucous  la- 
mina is  made  to  exhibit,  very  satisfactorily,  the  villous  and 
spongy  appearance.  This  is  particularly  evident  on  the  turbi-. 
nated  bones.  Its  whole  surface  is  studded  with  pits  or  folli- 
cles of  various  sizes,  irregularly  arranged  and  resembling  pricks 
made  into  a  plastic  substance  with  the  point  of  a  pin.  From 
these  cavities  or  cryptae  proceeds  the  mucus  of  the  nose.  In  the 
thickness  of  the  pituitary  membrane,  there  exist  numerous  and 
thickly  set  glands,  of  a  size  so  small  that  they  escape  common 
observation,  but  their  existence  is  generally  admitted,  both  on 
the  authority  of  anatomists  who  have  described  them,*  and  on 
the  principle  of  their  being  always  the  concomitants  of  mucous 
membranes.f 

Jt  is  owing  to  the  great  abundance  of  blood  vessels  in  this 
membrane,  to  their  very  superficial  course,  and  to  the  habitual 

*  Ruyschii,  Epist.  Anat.  Probl,  vii.     Mayer, 
f  Bicliat,  Anat.  Descrip. 


ORGAN  OP  SMELLING.  389 

residence  of  blood  in  them,  that  it  always  presents  a  deep  red 
colour  in  the  living  state.  These  blood  vessels  bleed  very 
freely  from  slight  mechanical  causes,  and  are  also  disposed  to 
congestions,  which  are  relieved  by  the  blood  being  poured  out 
through  their  exhalent  orifices,  withoift  laceration  or  any  solu- 
tion of  continuity. 

Though  the  description  just  given  corresponds  with  the  tex- 
ture, generally,  of  the  pituitary  membrane,  yet  there  are  modi- 
fications of  the  latter  at  particular  points  which  it  does  not  fully 
suit.  For  example,  at  the  anterior  orifice  of  the  nostril  it  is 
insensibly  changed  into  a  thin  skin,  furnished  in  the  male  adult 
with  stiff  hairs  (  Vibrissse;}  and  in  all  the  sinuses  it  is  more  thin 
and  white  than  elsewhere,  being  also  smooth  and  shining,  and 
not  presenting  clearly  the  little  pits  which  are  so  distinct  in  the 
nose.  The  surface  which  adheres  to  the  sides  of  the  sinuses, 
is  destitute  of  a  fibrous  structure,  and  is  so  loosely  attached  that 
it  peels  off  with  a  very  inconsiderable  force.  When  the  mem- 
brane of  the  sinuses  is  inflamed,  it  then  thickens,  admits  more 
red  blood,  and  is  thus  brought  to  resemble  the  pituitary  else- 
where. 

It  is  extremely  difficult  to  assign  a  proper  use  to  the  sinuses 
bordering  on  and  entering  into  the  nose;  for,  accprding  to  Des- 
sault,  the  sensation  of  smell  does  not  exist  in  them.  Bichat  be- 
lieved that  they,  by  being  filled  with  air  charged  with  odorous 
particles,  were  reservoirs  of  the  latter,  serving  to  prolong  the 
sensation  of  smell,  which  would  have  been  too  fugitive  if  it  had 
depended  only  on  the  passage  of  air  during  respiration.  Ano- 
ther problem  in  regard  to  these  cavities,  is  the  manner  in  which 
they  discharge  the  mucus  which  they  secrete.  Perfectly  rigid 
and  unyielding,  and  so  situated  that  the  most  frequent  attitudes 
of  the  head  would  rather  serve  to  retain,  than  to  discharge  the 
contents  of  most  of  them  by  gravitation,  we  yet  seldom  see 
more  than  their  surface  smeared  with  mucus,  and  accumulations 
of  it  are  quite  uncommon,  except  in  the  diseased  state.  The  se- 
cretion in  them,  it  is  to  be  observed,  is  much  less  abundant  than 
it  is  in  the  nose. 

VOL.  II.— 50      ' 


390  NERVOUS  SYSTEM. 


Of  the  Nerves  of  the  Pituitary  Membrane.* 

The  pituitary  membrane  is  furnished  with  nerves  from  two 
sources;  from  the  olfactory,  and  from  the  fifth  pair. 

The  Olfactory  Nerve  having  formed  its  bulb,  which  reposes 
in  the  ethmoidal  fossa,  sends  off  from  the  under  surface  of  the 
bulb,  the  succession  of  filaments  which  penetrate  to  the  nose 
through  the  cribriform  plate  of  the  ethmoidal  bone.  The  lat- 
ter, when  examined  from  the  upper  surface,  has  its  foramina  ar- 
ranged into  two  rows,  one  next  to  the  crista  galli,  and  the  other 
next  to  the  cellular  portion  of  the  ethmoid.  Each  row  consists 
of  about  six  or  eight  foramina,  and  between  these  rows  there 
are  other  foramina,  smaller,  and  not  so  much  in  a  line  with  each 
other.  The  same  cribriform  foramina,  when  examined  from 
the  cavity  of  the  nose,  are  more  numerous,  especially  those  be- 
longing to  the  two  first  rows,  in  consequence  of  the  latter 
branching  out  below  into  several  canals,  which  may  be  seen 
very  distinctly  on  the  side  of  the  base  of  the  nasal  lamella,  and 
on  that  of  the  cellular  portion  of  the  ethmoid. 

The  distribution  of  the  olfactory  nerve  corresponds  with  this 
arrangement  of  the  cribriform  plate,  for  it  has  three  rows  of 
branches  proceeding  from  the  under  surface  of  its  bulb,  each 
branch  going  through  its  appropriate  foramen,  and  subdividing 
in  it,  but  sometimes  two  filaments  pass  through  the  same  fora- 
men. In  a  short  space  after  their  origin,  they  become  invested 
by  sheaths  of  the  dura  mater,  which  are  extended  a  considera- 
ble distance,  and  which,  by  a  close  adhesion  to  the  nerves,  make 
them  appear  much  larger  below  than  they  are  at  the  roots. 
When  the  nerves  reach  the  cavity  of  the  nose  they  anastomose 
together,  and  descending  between  the  bone  and  the  pituitary 
membrane,  they  ramify  into  an  infinitude  of  small  branches,  the 
terminating  filaments  of  which  reach  the  nasal  surface  of  the 
membrane. 

The  Internal  Branches,  or  those  next  to  the  crista  galli,  di- 
verge from  the  cribriform  plate,  and  pass  downward  between 

*  Antonii  Scarpa,  Anatom.  Annotationes,  Lib.  ii. 


ORGAN  OP  SMELLING.  391 

the  septum  and  the  pituitary  membrane :  where  they  first  appear 
in  the  nose,  there 'are  some  few  adhesions  or  anastomoses  be- 
tween them ;  but  their  filaments  afterwards  keep  perfectly  dis- 
tinct, and,  spreading  themselves  out  on  the  pituitary  membrane 
of  the  septimi,  make  an  appearance  resembling  a  flat  camePs- 
hair  pencil.  The  middle  ones  are  the  longest,  and  may  be 
traced  almost  to  the  floor  of  the  nose ;  the  anterior  are  shorter 
somewhat ;  the  posterior  do  not  reach  obviously  below  the  middle 
of  the  septum. 

The  External  Branches  have  a  very  different  mode  of  distri- 
bution. While  still  in  their  canals  they  divide  into  many  fila- 
ments, which  anastomose  frequently  with  each  other,  and  when 
they  have  fairly  got  into  the  cavity  of  the  nose,  the  same  fre- 
quency of  anastomosis  continues,  so  that  they  form  a  net- work  of 
numerous  and  small  meshes,  which  prevails  from  the  cribriform 
plate  to  the  inferior  margin  of  the  middle  turbinated  bone.  Their 
filaments  cannot  be  traced  below  the  latter  line,  and,  therefore, 
do  not  descend  so  low  as  the  filaments  of  the  internal  row,  nei- 
ther are  they  so  close  to  each  other.  They  do  not  penetrate  to 
the  ethmoidal  cells.  The  posterior  ones  are  very  abundant,  on 
the  upper  turbinated  bone,  and  incline  backwards  in  their  de- 
scent ;  the  anterior  are  also  abundant  on  the  flat  anterior  half  of 
the  ethmoid,  and  when  they  get  below  the  line  of  the  upper 
meatus,  they  extend  backwards  to  the  posterior  end  of  the  mid- 
dle turbinated  bone,  and  to  its  inferior  margin.  On  this  bone 
they  are  less  abundant  than  above  it;  their  meshes  are  larger, 
and  their  distribution  is  confined  to  the  Schneiderian  membrane 
covering  its  convex  surface. 

The  filaments  of  the  middle  row  associate  themselves  indis- 
criminately with  those  of  the  external  and  of  the  internal  row, 
according  to  local  convenience. 

The  other  nerves  of  the  Pituitary  Membrane .  come  from  the 
first  and  from  the  second  branch  of  the  Trigeminus.  The  first 
branch  gives  off  from  its  nasal  branch  the  nerve  called  Internal 
Nasal,  which  penetrates  from  the  orbit  into  the  cavity  of  the 
cranium,  through  the  anterior  internal  orbitary  foramen,  and  lies 
covered  by  the  dura  mater,  at  the  side  of  the'crista  galli;  thence 


392  NERVOUS  SYSTEM. 

it  passes  into  the  cavity  of  the  nose  through  the  most  anterior 
foramen  of  the  cribriform  plate. 

This  Internal  Nasal  Nerve  (Nasalis  Intermix)  having  got  into 
the  nose,  divides  into  two  fasciculi,  an  internal  and  |in  external. 
The  internal  descends  along  the  anterior  margin  of  the  septum, 
between  the  mucous  membrane  and  the  bone,  and,  after  a  short 
course,  is  divided  into  two  filaments,  one  of  which,  applying  it- 
self to  the  posterior  face  of  the  os  nasi,  terminates  by  smaller 
filaments  in  the  integuments  of  the  lower  part  of  the  nose;  the 
other  filament  continues  along  the  margin  of  the  septum  to  the 
lower  part  of  the  latter,  where  it  terminates  by  smaller  filaments. 
The  external  fasciculus  of  the  Nasalis  Internus  gives  off  early  a 
filament,  which  descends  along  a  groove  on  the  posterior  face 
of  the  nasal  bone,  and  winding  over  the  lower  edge  of  the  latter, 
or  passing  through  a  foramen  in  it,  is  lost  upon  the  integuments 
of  the  corresponding  part  of  the  nose.  Other  filaments  from 
the  external  fasciculus  descend  upon  the  mucous  membrane, 
along  the  external  anterior  part  of  the  nose,  or  that  which- cor- 
responds with  the  nasal  process  of  the  upper  maxilla,  and  ter- 
minate near  the  anterior  extremity  of  the  inferior  spongy  bone: 
they  are  three  or  four  in  number.  The  internal  nasal  nerve  is 
also  said  to  send  one  or  more  filaments  to  the  frontal  sinuses,  but 
they  are  so  fine  that  doubts  of  their  existence  are  entertained 
by  Bichat,  though  they  are  admitted  by  J.  F.  Meckel. 

The  Spheno-Palatine  Ganglion,  a  part  of  the  second  branch  of 
the  Trigeminus,  detaches  to  the  nose,  through  the  spheno-palatine 
foramen,  several  filaments.  One  of  these,  discovered  by  Cotun- 
nius,  and  admirably  delineated  by  Scarpa  and  by  John  Hunter, 
called  the  Naso  Palatinus,  runs  across  the  front  of  the  sphenoidal 
sinus  to  the  upper  posterior  part  of  the  septum  narium,  beneath 
the  mucous  membrane.  It  then  descends  obliquely  along  the 
septum  to  the  foramen  incisivum,  and  passes  through  it  to  the 
roof  of  the  mouth.  In  many  cases,  however,  a  distinct  foramen 
is  formed  in  the  middle  palate  suture  for  it,  anterior  to  the  fora- 
men incisivum.  The  nerve  of  the  left  side  is  anterior  to  that  on 
the  right.  When  the  two  reach  the  roof  of  the  mouth,  or  are 
near  it,  they  unite  to  form  a  little  swelling,  called  the  naso-pa- 


ORGAN  OF  SMELLING.  393 

latine  ganglion,*  from  which  several  filaments  arise  and  are 
spent  upon  the  membranous  caruncle  at  this  point,  and  upon  the 
contiguous  part  of  the  palatine  membrane. 

The  spheno-palatine  ganglion  sends  several  filaments  to  the 
mucous  membrane  of  the  upper  spongy  bone  and  of  the  upper 
meatus,  and  to  that  of  the  posterior  end  of  the  middle  spongy 
bone.  The  palatine  nerve,  one  of  its  largest  branches,  in  de- 
scending along  the  posterior  palatine  canal  to  the  soft  palate  of 
the  mouth,  also  contributes  to  the  supply  of  nerves  to  the  nose. 
Shortly  after  it  has  arisen  from  the  ganglion,  it  sends  one  or 
more  filaments  to  the  middle  spongy  bone,  and  to  the  superior 
part  of  the  lower  spongy  bone,  and  when  it  has  got,  in  its  descent, 
on  a  level  with  the  posterior  end  of  the  latter,  it  detaches  another 
filament,  which  supplies  the  mucous  membrane,  along  the  infe- 
rior margin  of  this  bone. 

An  opinion  advanced  by  Mery  about  the  close  of  the  seven- 
teenth century,  has  lately  been  revived  by  M.  Magendie,  of  Paris, 
that  the  olfactory  nerves  are  not  those  which  communicate  the 
impressions  of  odorous  bodies.  In  contradiction,  however,  to 
his  experiments,  it  should  be  stated,  that  several  respectable 
anatomists  have  seen  cases  where  the  privation  of  the  sense  of 
smell  during  life,  was  found,  upon  examination  after  death,  to  be 
attended  with  the  absence  of  the  olfactory  nerves, 

Of  the  Blood  Vessels  of  the  Nose. 

The  extreme  vascularity  of  the  Schneiderian  Membrane  is 
derived  from  several  sources.  The  Internal  Maxillary  Artery 
sends  through  the  Spheno-Palatine  Foramen  a  large  branch, 
which  is  distributed  upon  the  septum  and  upon  the  spongy  bones. 
The  palatine  artery  also  supplies  this  membrane  with  one  or 
more  small  branches.  The  Ophthalmic  also  sends  the  anterior 
and  the  posterior  ethmoidal  branches  to  it,  from  the  orbit  of  the 
eye.  The  infra-orbitar  artery  likewise  contributes  to  its  vas- 
cularity by  one  or  more  branches,  sent  off  in  its  course  through 
the  infra-orbitar  canal. 

*  J.  Cloquet,  Anat. 


394  NTERVOUS  SYSTEM. 

% 

The  veins  follow  the  course  and  distribution  of  the  arteries. 
Some  of  them,  however,  unite  with  the  trunks  called  emissaries 
of  Santorini,  which  reach  the  sinuses  of  the  brain  through  the 
foramen  ovale  and  rotundum  of  the  sphenoid  bone. 


CHAPTER  II. 


OF  THE  EYE,  AND  ITS  DEPENDENCIES. 

THE  organ  of  vision  which  depends  upon  the  optic  nerve  for 
its  usefulness,  is  formed  by  the  Ball  of  the  Eye  and  many  Depen- 
dencies or  Auxiliary  parts,  all  of  which  are  situated  within  the 
orbit,  and  fill  up  its  cavity. 


SECT.  I. OF  THE  AUXILIARY  PARTS  OF  THE  EYE. 

The  Eyelids  (Palpebra)  are  placed  at  the  anterior  orifice  of 
the  orbit,  and  serve  to  shut  out  the  light  from  the  eye,  by  their 
closing ;  and  also,  by  their  frequent  motions,  to  sweep  the  front 
of  the  eyeball,  so  as  to  remove,  from  its  transparent  part,  moats 
and  dust.  They  are  distinguished  into  upper  and  lower,  and 
the  place  at  each  end,  where  the  horizontal  fissure  between  them 
ceases,  is  called  their  Commissure,  Angle  or  Canthus.  The  angle 
next  to  the  nose,  or  the  internal,  is  called  the  Great  one,  and  the 
other,  the  Little  one. 

The  Internal  Canthus  is  united  to  the  nasal  process  of  the  su- 
perior maxillary  bone  by  a  rounded  tendon,  (Ligamentum  Palpe- 
brale  Internum,)  which  passes  horizontally  inwards,  and  is  nearly 
half  an  inch  in  length.  It  throws  the  skin  into  a  small  ridge, 
which  may  be  distinctly  seen  and  felt  at  this  point.  The  Exter- 
nal Canthus  is  held  in  place  by  its  general  attachments  of  cellu- 
lar substance  and  by  the  external  palpebral  ligament. 

The  upper  eyelid  is  somewhat  larger  than  the  lower,  but  the 
structure  of  both  is  the  same,  for  each  one  is  formed  by  skin  ex- 


THE  EYE.  395 

ternally;  next  to  it  a  plane  of  muscular  fibres,  being  the  orbicu- 
laris  palpebrarum;  then  a  plate  of  cartilage;  and,  lastly,  a  thin 
membrane  uniting  it  to  the  eyeball. 

There  is  nothing  in  the  texture  of  the  skin  of  the  eyelid  which 
needs  description  in  a  more  particular  manner,  than  that  of 
stating  its  fineness,  its  thinness,  the  looseness  of  its  attachment 
to  the  muscle  beneath  by  long  yielding  cellular  substance,  and 
the  deficiency  of  adipose  matter.  It  is  rendered  prominent  at 
the  superior  margin  of  the  orbit,  both  by  the  projection  of  the  bone 
there,  and  by  the  presence  of  the  corrugator  supercilii  muscle 
at  its  internal  extremity.  This  prominence  is  furnished  with  an 
arched  cluster  of  hairs,  (Supercilia,)  which  have  their  loose  ends 
inclined  horizontally  outwards,  and  are  rather  more  abundant 
at  the  root  of  the  nose  than  externally.  The  supercilia  of  the 
two  sides  are  separated  commonly  by  a  small  bare  space  called 
Glabella,  the  existence  of  which  adds  much  to  the  calm  and  in- 
tellectual expression  of  the  human  countenance ;  whereas,  the 
junction  of  the  two  eyebrows,  by  the  hairs  filling  up  this  space, 
gives  a  gloomy,  and,  occasionally,  a  ferocious  appearance. 

The  margins  of  the  eyelids  are  also  furnished  with  hairs, 
(Cilia,)  the  roots  of  which  are  insinuated  between  the  skin  and 
the  tarsus  cartilage:  the  most  deeply  seated  seem,  indeed,  to  pe- 
netrate the  latter.  The  hairs  of  the  upper  lid  are  longer  and 
more  numerous  than  those  of  the  lower;  they  are  concave  up- 
wards, while  the  latter  are  concave  downwards,  so  that  the  con- 
vexities of  the  two  ranges  of  hairs  come  in  contact  when  the 
eyelids  are  closed.  The  hairs  of  each  cilium  are  disposed  into 
three  or  four  rows,  by  which  a  long  brush  is  formed,  the  central 
hairs  of  which  are  longer  and  larger  than  any  others. 

The  hairs  of  the  supercilia  and  of  the  cilia  resemble  one  ano- 
ther strongly,  for,  when  examined  closely,  each  one  will  be  found 
to  have  a  bulbous  soft  root,  just  beyond  which  there  is  a  narrow 
part.  The  middle  of  the  hair  is  swollen,  and  its  external  extre- 
mity is  brought  to  a  fine  point.  These  hairs  correspond  in  co- 
lour with  the  hairs  of  the  head. 

When  the  orbicularis  muscle  is  removed,  a  ligamentous  or 
fibrous  membrane  is  found  passing  from  the  external  margin  of 
the  orbit  to  the  corresponding  margin  of  the  palpebral  cartilages, 


396  NERVOUS  SYSTEM. 

and  separating  the  eyelids  from  the  parts  contained  within  the 
orbit.  There  is  a  partial  decussation  of  the  fibres  of  this  mem- 
brane, from  the  external  commissure  of  the  cartilages  to  the  ex- 
ternal edge  of  the  orbit ;  it  has  more  firmness  than  any  other 
part  of  the  membrane,  and  is  the  external  palpebral  ligament, 
(Ligamentum  Palpebrale  Externum.)  On  the  side  of  the  internal 
canthus  of  the  orbit  there  is  no  corresponding  ligamentous  ex- 
pansion, but  a  few  irregular  fibres,  which  allow  the  masses  of 
fat  beneath  to  project  forwards  between  their  fasciculi. 

The  Palpebral  Cartilages  (Tarsi)  are  two  in  number,  one  at 
the  margin  of  each  eyelid,  to  which  they  communicate  a  smooth, 
even  surface,  from  the  internal  to  the  external  commissure. 
They  are  between  the  orbicularis  muscle  and  the  tunica  conjunc- 
tiva. The  upper  one  is  larger  than  the  lower,  resembles  an  oval 
cut  in  half  in  its  long  diameter,  and  is  about  six  lines  broad  in 
its  middle :  the  lower  one  is  of  a  breadth,  nearly  uniform,  of 
about  two  lines.  Their  internal  extremities  cease  just  before 
they  reach  the  puncta  lachrymalia,  and  are  attached  to  the  in- 
ternal palpebral  ligament,  which  has  been  described  as  one  of  the 
origins  of  the  orbicularis  oculi  muscle,  at  the  nasal  process  of 
the  upper  maxillary  bone ;  their  external  extremities  cease  just 
before  their  commissure,  and  are  firmly  attached  to  the  external 
palpebral  ligament. 

These  cartilages  are  thicker  where  they  form  the  margin  of 
the  eyelids,  and  have  there  a  slope  or  bevel,  by  which,  when  in 
contact,  a  small  groove  is  formed  on  their  posterior  surface. 
From  their  resistance  to  the  concentric  contractions  of  the  or- 
bicularis, they  keep  the  eyelid  smooth,  and  favour  its  sliding 
upon  the  eyeball.  Certain  animals,  being  destitute  of  these  car- 
tilages, when  they  wink,  the  skin,  by  the  contraction  of  the  or- 
bicularis, is  drawn  up  like  the  mouth  of  a  purse. 

Conjunctiva. — Below  the  palpebral  cartilage  is  the  fourth  layer 
of  the  eyelid,  the  conjunctiva.  It  is  a  white,  thin,  and  diapha- 
nous membrane,  in  the  uninflamed  state.  Beginning  at  the  roots 
of  the  cilia,  where  it  is  continuous  with  the  skin,  it  covers  the 
posterior  face  of  each  eyelid,  is  reflected  for  eight  or  ten  lines 
towards  the  bottom  of  the  orbit,  and  then  passes  to  the  eyeball, 


THE  EYE.  397 

of  which  it  covers  the  anterior  half,  not  excepting  the  cornea. 
It  penetrates  into  the  lachrymal  passages,  to  be  continuous  with 
the  lining  membrane  of  the  lachrymal  sac. 

From  this  description,  it  is  evident  that  the  tunica  conjunctiva 
has  one  surface  presented  against  itself  when  the  eyelids  are 
closed;  this  surface  is  lubricated  and  very  smooth,  so  as  to  per- 
mit a  free  motion  of  the  lids  and  ball  of  the  eye.  The  other 
surface  is  connected  in  its  anterior  half  by  cellular  substance  to 
the  eyelids,  and  in  its  remaining  part  to  the  ball  of  the  eye,  by 
the  same  means.  It  is  united  rather  loosely  to  the  sclerotica  till 
it  gets  near  the  margin  of  the  cornea;  but  to  the  latter  it  ad- 
heres so  firmly,  and  changes  there  so  much  its  texture,  that  it 
seems  like  a  portion  of  the  cornea. 

This  membrane,  from  its  continuity  with  the  skin  and  the 
lining  membrane  of  the  nose,  from  its  sympathies  with  them, 
from  the  nature  of  the  discharge  from  it,  and  from  its  extreme 
sensibility,  is  ranked  by  Bichat  among  the  mucous  membranes. 
It  has,  however,  some  peculiarities  in  its  structure,  for  it  is  en- 
tirely deficient  in  villosities,  and  though  most  abundantly  fur- 
nished with  capillary  vessels,  they  do  not  obviously  admit  red 
blood,  but  in  a  state  of  irritation. 

Glandule  Palpebrarum. — These  bodies,  also  called  the  glands 
of  Meibomius,  from  an  anatomist  who  has  described  them  par- 
ticularly, are  situated  at  the  margin  of  each  eyelid,  between  its 
cartilage  and  the  conjunctiva.  They  are  about  two  or  three 
lines  long,  and  appear  like  small,  white,  serpentine  threads,  run- 
ning at  right  angles  to  the  margin  of  the  lid,  near  to,  and  paral- 
lel with  one  another.  They  are  more  abundant  on  the  upper 
than  on  the  lower  lid.  They  terminate  by  a  row  of  small  ori- 
fices in  the  margin  of  the  lid,  just  behind  the  cilium.  For  prevent- 
ing the  overflowing  of  the  tears,  and  the  sticking  together  of  the 
eyelids,  they  discharge  an  unctuous  fluid,  which  may  be  made 
manifest  by  squeezing  them.  Their  secretion  is  occasionally 
much  augmented,  and  then  has  a  large  quantity  of  serum  and 
glutinous  matter  in  it :  in  this  case  the  evaporation  of  the  serum 
makes  it  adhesive,  and  causes  the  eyelids  to  adhere  after  they 
have  been  closed  for-  some  time,  as  in  sleep. 

VOL.  II.— 51 


398  NERVOUS  SYSTEM. 

Muscles. 

f  The  Musculus  Levator  Palpebrae  Superioris  is  placed  in  the 
superior  part  of  the  orbit.  It  arises  by  a  small  round  tendon 
from  the  upper  margin  of  the  optic  foramen,  and,  becoming 
fleshy,  it  expands  itself  into  a  long  thin  triangle,  of  which  the 
base  is  in  front.  It  covers  the  rectus  superior  muscle. 

Terminating  in  front  by  a  thin  tendinous  expansion,  it  is  in- 
serted into  the  superior  margin  of  the  upper  palpebral  cartilage ; 
but  some  of  its  fibres  continue  on  between  the  latter  and  the  or- 
bicularis  to  the  lower  edge  of  the  cartilage. 

It  raises  the  upper  lid,  by  drawing  it  towards  the  bottom  of 
the  orbit. 

There  are  six  muscles  concerned  in  moving  the  eyeball,  four 
of  which,  from  their  direction,  are  said  to  be  straight ;  and  the 
other  two,  for  the  same  reason,  are  called  oblique.  With  the 
exception  of  the  inferior  oblique,  they  all  arise  from  the  bottom 
of  the  orbit. 

1.  The  Rectus  Oculi  Superior,  being  placed  immediately  be- 
low the  levator  palpebrse,  arises  from  the  superior  margin  of  the 
optic  foramen.     It  runs  forward,  increasing  somewhat  in  breadth, 
and  is  inserted  by  a  broad  thin  tendon  into  the  sclerotica,  two 
lines  from  the  cornea. 

It  turns  the  eye  upwards. 

2.  The  Rectus  Oculi  Externus  arises  from  the  external  mar- 
gin of  the  optic  foramen.     It  then  advances  along  the  middle  of 
the  external  wall  of  the  orbit,  near  the  periosteum,  to  which  it 
adheres  slightly,  and  is,  finally,  inserted,  by  a  thin  broad  tendon, 
into  the  external  side  of  the  sclerotica,  about  two  or  three  lines 
from  the  cornea. 

It  abducts  the  eye,  or  turns  its  outwards. 

3.  The  Rectus  Oculi  Inferior  arises  also  from  the  optic  fora- 
men, at  its  inferior  margin,  and,  lying  upon  the  floor  of  the  orbit 


THE  EYE.  399 

as  it  advances  forwards ;  it  is  inserted,  tendinous,  into  the  under 
surface  of  the  sclerotica,  two  lines  from  the  cornea. 
It  depresses  the  eye,  or  turns  it  downwards. 

4.  The  Rectus  Oculi  Internus  arises  from  the  internal  margin 
of  the  optic  foramen,  and  goes  forwards  along  the  internal  wall 
of  the  orbit,  being  separated  from  it  by  a  layer  of  adipose  mat- 
ter.    It  is  inserted,  by  a  tendinous  expansion,  into  the  inner  side 
of  the  sclerotica,  two  or  three  lines  from  the  cornea. 

It  adducts  the  eye,  or  turns  it  inwards. 

5.  The  Obliquus  Oculi  Superior  is  placed  along  the  upper' in- 
ternal angle  of  the  orbit.     It  arises  from  the  corresponding  mar- 
gin of  the  optic  foramen,  by  a  small  round  tendon;  it  then  ad- 
vances forwards,  and  when  it  has  got  near  the  margin  of  the 
orbit,  it  is  converted  into  a  long  round  tendon. 

The  tendon  passes  through  a  cartilaginous  loop  which  is 
formed  for  it,  just  at  the  inner  margin  of  the  supra  orbitary  fo- 
ramen, and  is  connected  to  the  loop  by  long  loose  cellular  sub- 
stance, which  permits  it  to  play  freely  backwards  and  forwards. 
The  tendon  from  this  point  changes  its  direction  by  going  back- 
wards and  outwards:  it  also  becomes  more  flat,  and  is  then  in- 
1  serted  into  the  upper  face  of  the  sclerotica  near  its  middle,  just 
beneath  the  internal  margin  of  the  rectus  superior  muscle. 

This  muscle  is  the  longest,  but  the  most  delicate  of  those  be- 
longing to  the  eyeball.  According  to  Scemmering,  it  draws  the 
eyeball  forwards,  and  towards  the  internal  canthus,  and  directs 
the  pupil  towards  the  cheek.  By  the  aid  of  the  inferior  oblique, 
it  draws  the  eyeball  towards  the  nose :  it  expresses  pride :  it  ap- 
pears to  be  greatly  excited  in  anger.* 

The  preceding  muscles  are  all  connected,  either  directly  or 
indirectly,  with  the  theca  of  the  optic  nerve. 

6.  The  Obliquus  Oculi  Inferior  is  at  the  bottom  of  the  orbit. 

*  Bulbum  in  priora  et  angulum  internum  versus  movet;  pupillam  deorsura  ad 
genam  dirigit;  juvante  musculo  obliquuo  inferiorc  bulbum  nasum  versus  trahit $ 
animi  fastum  exprimit;  ira  valde  commoveri  videtur. 


400  NERVOUS  SYSTEM. 

It  arises,  by  a  small  tendinous  beginning,  from  the  os  maxillare 
superius  at  the  side  of  the  os  unguis,  and,  increasing  in  size,  it 
goes  below  the  rectus  inferior  outwards  and  backwards,  and 
gets  between  the  eyeball  and  the  rectus  externus.  It  is  then  in- 
serted into  the  outer  face  of  the  sclerotica,  about  half  way  be- 
tween the  optic  nerve  and  the  cornea. 

It  causes  the  eye  to  revolve  on  its  axis,  and  turns  the  cornea 
towards  the  nose.  Its  action,  however,  is  much  modified  by  that 
of  the  other  muscles.  As  one  axis  of  the  eye  is  a  line  passing 
from  the  centre  of  the  optic  nerve,  forwards  and  outwards,  it 
will  be  found  that  each  of  the  oblique  muscles  is  inserted,  at 
right  angles,  to  this  line;  consequently,  their  simple  and  un- 
modified action  is  to  produce  a  revolution  of  the  eye,  on  its  axis, 
in  the  line  of  their  insertion,  the  first  making  the  eye  roll  in- 
wards, and  the  latter  outwards,  on  the  two  poles:  they,  there- 
fore, are  strictly  antagonists.  I 

Of  the  Lachrymal  Apparatus. 

The  apparatus  for  the  tears  (Organa  Lachrymalia,  vice  Lachry- 
males)  consists  in  the  Lachrymal  Gland,  the  Lachrymal  Ducts, 
the  Lachrymal  Sac,  and  a  few  other  parts. 

The  Lachrymal  Gland  ( Glandula  Lachrymalis)  is  situated  in 
the  orbit,  immediately  below  and  within  the  external  angular 
process  of  the  os  frontis.  It  secretes  the  moisture  that  lubri- 
cates the  eyelids  and  eyeball,  and  which,  when  it  becomes  abun- 
dant, is  called  the  Tears.  It  is  a  flattened  oblong  or  oval,  con- 
vex above  and  concave  below,  of  ten  lines  in  length,  six  in 
width,  and  about  two  lines  at.  its  thickest  part,  for  its  edges  are 
somewhat  bevelled.  It  may  be  considered  as  divided  into  two 
parts  or  lobes,  of  which  the  superior  is  the  larger  and  occupies 
the  depression  attributed  to  it  in  the  frontal  bone,  while  the  in- 
ferior, being  the  smaller,  is  placed  at  the  anterior  margin  of  the 
depression.*  It  is  lined  below  by  the  conjunctiva,  and  is  pro- 
tected in  front  by  the  margin  of  the  orbit  which  it  touches. 

This  gland  resembles  much  a  salivary  gland  in  its  light  pink 
colour,  and  in  its  consisting  in  a  congeries  of  lobules  united  by 

*  These  lobes  are  frequently  marked  off  by  a  lig-amentous  band  passing-  from 
between  them  to  the  .external  angular  process. 


THE  EYE.  401 

cellular  substance.  Unless  we  are  to  consider  the  latter  as  such, 
it  has  no  regular  capsule.  From  the  lachrymal  gland  there  pro- 
ceed six  or  seven  excretory  canals,  extremely  fine,  and  found 
with  so  much  difficulty  that  many  distinguished  anatomists  have 
sought  for  them  in  vain.*  The  orifices  of  these  ducts  have  been 
laid,  down,  by  Soemmering,  as  equi-distant;  forming  in  the  con- 
junctiva, a  row  half  an  inch  long,  and  parallel  with  the  superior 
margin  of  the  upper  tarsus  cartilage,  beginning  a  quarter  of  an 
inch  above  its  external  end  and  going  inwards.  By  squeezing 
the  gland,  small  drops  like  tears,  will  appear  on  the  nearest  sur- 
face of  the  conjunctiva,  but  not  in  the  regular  order  laid  down 
by  anatomists  for  the  lachrymal  orifices. 

The  Lachrymal  Ducts  (Canaliculi  Lachry males)  are  situated 
immediately  beneath  the  skin,  at  the  internal  commissure  of  the 
eyelids,  in  their  posterior  margin,  and  behind  the  orbicularis 
muscle.  There  is  one  for  each  eyelid.  They  are  about  half 
an  inch  long,  though  the  lower  one  is  rather  longer  than  the 
upper. 

The  lachrymal  ducts  commence  at  a  small  elevation  of  the 
margin  of  each  eyelid,  bordering  immediately  upon  the  internal 
end  of  the  tarsus  cartilage,  but  perfectly  distinct  from  it.  This 
elevation  is  conical,  has  a  vermicular  motion  during  life,  and 
points  towards  the  ball  of  the  eye ;  in  its  centre  is  a  very  small 
foramen,  called  the  Punctum  Lachrymale,  which  is  the  begin- 
ning of  the  lachrymal  duct.  The  punctum  is  about  a  line  in 
length;  and  enlarging  in  its  course,  it  runs  at  right  angles  to  the 
duct  into  which  it  empties,  of  which  it  may  be  called  the  Orbital 
Orifice:  the  upper  one  will,  therefore,  ascend,  and  the  lower  one 
descend. 

The  lachrymal  ducts  are  much  larger  than  the  puncta,  and 
are  in  their  whole  course  about  one  line  in  diameter.  At  their 


*  These  are  Morgagni,  Haller,  Zinn,  and  Durverney.  Meckel,  Scemmering, 
and  many  others,  speak  with  all  confidence  concerning  them.  Bichat  admits 
that  he  only  acknowledges  their  existence  inductively.  Dr.  Monro,  of  Edinburgh, 
claims  to  have  discovered  them  by  plunging  the  eye  into  a  coloured  fluid  which 
was  absorbed  by  them.  Dr.  W.  Hunter  seems  to  have  a  prior  claim  to  Dr. 
Monro.  See  Mcd.  Comment,  p.  54.  Mascagni  also  acknowledges  their  exist- 
ence:—Prodromo  della  Grande  Anatomia,  vol.  i.  p.  60. 


402  NERVOUS  SYSTEM. 

orbital  extremities,  they  go  rather  beyond  the  puncta,  so  as  to 
form  a  small  cul-de-sac.  These  canals  converge,  and  having 
got  to  the  internal  angle  of  the  eyelid,  they  are  there  placed  be- 
hind the  internal  palpebral  ligament.  They  then  discharge,  by 
distinct  orifices,  but  very  near  each  other,  into  the  lachrymal  sac 
at  its  external  anterior  part,  where  they  form  a  small  round  pro- 
jection into  the  interior  of  its  cavity,  and  are  overlapped,  some- 
times, by  a  small  duplicature  of  its  lining  membrane.  When  the 
eyelids  are  closed,  the  lachrymal  ducts  are  horizontal  and  nearly 
parallel,  but  when  the  eye  is  open  the  upper  duct  is  elevated, 
and  thereby  becomes  oblique ;  it  is  hence  more  proper  for  the 
introduction  of  the  instruments  into  the  lachrymal  sac. 

The  Lachrymal  Caruncle  (Caruncula  Lachrymalis]  is  placed 
in  the  angle  formed  by  the  internal  junction  of  the  eyelids.  It 
is  a  red-coloured  tubercle,  differing  in  size  in  different  individuals, 
but  commonly  as  large  as  a  grain  of  wheat.  It  is  conical,  and 
obtains  its  redness  from  the  conjunctiva  being  reflected  over  it: 
when  accurately  examined,  it  will  be  found  to  consist  in  a  group 
of  sebaceous  glands ;  of  which,  according  to  some  anatomists, 
there  are  "seven  ranged  two  in  a  row,  and  one  on  the  top  of  the 
others.  The  surface  of  this  body  is  beset  with  very  fine  hairs, 
and  the  orifices  in  it  are  distinguishable  with  a  glass. 

The  Semilunar  Valve,  or  Fold,  (Plica  Semilunaris,)  is  situated 
immediately  at  the  outer  margin  of  the  caruncle.  It  has  the 
form  of  a  triangle,  the  point  of  which  runs  into  the  caruncle,  and 
the  base,  which  is  somewhat  crescentic,  is  directed  towards  the 
eye.  It  is  a  duplicature  of  the  conjunctiva,  becomes  very  mani- 
fest from  behind,  and,  in  some  cases,  has  its  base  furnished  with 
a  very  small  strip  of  cartilage.*  I  have  seen  several  cases  of 
the  kind  very  well  marked ;  they  occur  more  frequently  in  the 
African,  according  to  my  personal  experience.  Between  the 
base  and  the  caruncle  it  is  formed  into  a  number  of  loose  wrin- 
kles, which  disappear  when  the  eye  is  very  much  abducted. 

This  body,  in  the  human  subject,  is  evidently  intended  to  per- 
mit to  the  eye  a  great  freedom  of  abduction.  Its  analogy,  how- 

*  Meckel. 


THE  EVE.  403 

ever,  with  the  third  eyelid  of  animals  is  very  striking,  and  the 
difference  is  rather  in  the  full  development  of  the  latter,  than  in 
the  organization.  It  is  very  properly  remarked  by  J.  F.  Meckel, 
that  in  descending  the  scale  of  animals,  the  third  eyelid  is  al- 
ways in  an  inverse  ratio  to  the  other  two,  till  it  ends  by  being  a 
complete  substitute  for  them. 

Surrounding  the  caruncle,  may  be  observed  a  depression  on 
the  adjoining  part  of  the  plica  semilunaris.  Into  this  depression 
the  puncta  lachrymalia  are  directed,  and  there  play  up  and 
down:  the  tears  accumulate  in  it;  from  which  cause  the  depres- 
sion is  called  Lacus  Lachrymalis. 

The  Lachrymal  Sac  (Saccus  Lachrymalis)  is  placed  at  the  in- 
ternal canthus  of  the  orbit;  in  the  depression  of  the  os  unguis,  and 
of  the  nasal  process  of  the  upper  maxillary  bone.  It  is  an  ob- 
long cylindroid  cavity;  and  extends  from  the  transverse  facial 
suture  to  the  anterior  extremity  of  the  inferior  meatus  of  the 
nose;  being  concealed  there  by  the  anterior  part  of  the  inferior 
turbinated  bone.  It  is  crossed  at  its  front  part  by  the  tendon  of 
the  orbicularis,  which,  with  a  few  fibres  of  this  muscle,  adheres 
to  it. 

The  course  of  the  lachrymal  sac,  is,  at  first,  slightly  forwards 
in  the  descent  to  the  nose ;  but  when  it  reaches  the  lower  part 
of  the  orbit,  it  is  afterwards  slightly  backwards :  so  that  it  may 
be  considered  as  forming  an  obtuse  angle  forwards.  It  also  de- 
creases somewhat  in  size  from  above  downwards,  and  at  its 
lower  orifice  is  flattened  from  side  to  side. 

The  lachrymal  sac  consists  in  two  membranes,  an  exterior 
fibrous  one  continuous  with  the  periosteum  of  the  contiguous 
bones ;  and  an  interior  mucous  one,  which  is  thick,  villous,  of  a 
red  colour,  from  the  abundance  of  its  blood  vessels,  and  abound- 
ing in  mucous  follicles.  The  interior  is  continuous  above  with 
the  lachrymal  ducts,  and  below  with  the  Schneiderian  membrane. 
On  a  line  with  the  floor  of  the  orbit,  this  internal  membrane  is 
thrown  into  a  circular  duplicature,  considered  by  some  anatomists, 
as  forming  the  proper  boundary  of  the  lachrymal  sac:  all  below 
this  is  called  by  them  nasal  canal.  The  distinction  is  rather 
arbitrary,  and,  in  some  degree,  hurtful  to  clearness  of  descrip- 
tion: a  much  better 'plan  is  to  call  the  part  above  the  valve,  the 


404  NERVOUS  SYSTEM. 

orbital  portion  of  the  sac;  and  the  part  below  the  valve,  its  nasal 
portion.  Sometimes  there  is  a  second  valve  about  three  lines 
below  the  first,  and  generally  another  at  the  nasal  orifice,  formed 
by  a  duplication  of  the  Schneiderian  membrane. 

The  Tensor  Tarsi  is  a  small  muscle  on  the  orbital  face  of  the 
lachrymal  sac,  of  which  I  gave  a  detailed  account  some  few  years 
ago.*  It  arises  from  the  posterior  superior  part  of  the  os  un- 
guis,  just  in  advance  of  the  vertical  suture  between  the  os  pla- 
num  and  the  os  unguis.  Having  advanced  three  lines,  it  bifur- 
cates; one  bifurcation  is  inserted  along  the  upper  lachrymal 
duct,  and  terminates  at  its  punctum,  or  near  it;  and  the  lower 
bifurcation  has  the  same  relation  to  the  lower  lachrymal  duct. 
The  base  of  the  caruncula  lachrymalis  is  placed  in  the  angle  of 
the  bifurcation.  The  superior  and  the  inferior  margins  of 
the  muscle  touch  the  corresponding  fibres  of  the  orbicularis 
palpebrarum,  where  the  latter  is  connected  with  the  margin 
of  the  internal  canthus  of  the  orbit,  but  may  be  readily  dis- 
tinguished by  their  horizontal  course.  The  nasal  face  of  this 
muscle  adheres  very  closely  to  that  portion  of  the  sac  which  it 
covers,  and  also  to  the  lachrymal  ducts.  The  lachrymal  sac 
rises  about  a  line  above  its  superior  margin,  and  extends  in  the 
orbit  four  lines  below  its  inferior  margin.  The  orbital  face  of 
the  muscle  is  covered  by  a  lamina  of  cellular  membrane,  and 
between  this  lamina  and  the  ball  of  the  eye  are  placed  the  val- 
vula  semilunaris,  and  a  considerable  quantity  of  adipose  matter. 

As  the  bifurcated  extremities  of  the  muscle  follow  the  course 
of  the  ducts,  they  are  covered  by  the  tunica  conjunctiva.  When 
this  muscle  is  examined  from  behind,  the  eyelids  being  in  situ, 
it  becomes  obvious  that  it  is  concave  on  its  orbital  surface,  and, 
consequently,  convex  on  the  nasal;  that  the  muscle  is  an  oblong 
body,  half  an  inch  in  length,  and  about  three  lines  wide,  bifur- 
cated atone  end:  and  that  it  arises  much  deeper  from  the  orbit 
than  any  acknowedged  origin  of  the  orbicularis.  The  superior 
fork,  however,  has  a  few  of  its  fibres  blended  with  the  orbicu- 
laris. 

In  regard  to  the  use  of  this  muscle:  its  attachment  to  the 
posterior  face  of  the  sac  is  such,  that  it  draws  the  orbital  parts 

*  Philadelphia  Journal  of  Med.  and  Phys.  Sciences,  1824. 


THE  EYE.  405 

*)f  the  sac  away  from  the  nasal,  and  dilates  the  sac,  from  the  na- 
sal face  of  the  latter  being  fixed  to  the  bones.  As  this  mus- 
cle is  cylindrically  concave  on  its  orbital  side,  it  is  evident  that 
when  it  contracts,  the  fibres  become  straight,  or  nearly  so,  like 
the  fibres  of  the  diaphragm,  and  the  cavily  of  the  sac  is  enlarged 
after  the  same  manner  as  the  cavity  of  the  thorax.  A  tendency 
to  a  vacuum  being  thus  produced  by  it,  the  valves  or  folds  of  the 
internal  membrane  of  the  sac  permit  the  vacuum  to  be  filled 
more  readily  through  the  puncta  than  from  the  nose;  and  the 
puncta  being  continually  bathed  in  the  tears  of  the  lacus  lachry- 
malis,  both  in  the  waking  and  in  the  sleeping  state,  the  tears  are 
constantly  propelled  through  them  by  atmospheric  pressure. 
The  evacuation  of  the  sac  is  no  doubt  accomplished  by  its  own 
elasticity,  and  by  the  contraction  of  the  orbicularis;  probably 
in  a  chief  degree  by  the  latter,  because  in  persons  who  have 
epiphora,  or  a  tendency  to  obstruction  in  the  nasal  duct,  the  ac- 
cumulation of  tears  and  matter  principally  takes  place  at  night, 
when  the  action  of  the  orbicularis  is  suspended  by  sleep.  For 
these  reasons,  we  should  argue  that  this  little  muscle  is  active 
at  all  times,  both  night  and  day.  To  Dr.  Physick  I  am  indebt- 
ed for  suggesting  another  use  for  it;  to  wit,  that  of  keeping  the 
lids  in  contact  with  the  ball  of  the  eye.  Some  persons  posess 
unusual  voluntary  power  over  this  muscle,  of  which  I  have  seen 
several  examples.  In  each  instance  the  individual  could  short- 
en so  much  the  internal  angle  of  the  eyelids,  as  to  conceal  it, 
along  with  the  puncta,  in  the  internal  canthus  of  the  orbit* 

*  Having  laboured,  first  of  all,  to  convince  the  profession  of  the  existence  of 
this  muscle,  the  next  step,  as  is  usual  on  such  occasions,  was  to  vindicate  my  own 
pretensions  to  its  discovery,  and  to  attempt  to  remove  such  objections  as  re- 
quired attention.  For  the  arguments  on  this  subject,  I  refer  to  the  Philadelphia 
Journal  of  Medical  and  Physical  Sciences,  of  Nov.  1824,  edited  by  Professor  Chap- 
man. My  claims  have  been  unequivocally  admitted  by  Messrs.  Breschet  and 
Jourdan,  of  Paris,  anatomists  of  unusual  distinction,  in  the  translation  which  they 
have  made  of  J.  F.  Meckel's  Manual  of  Anatomy,  vol.  iii.  p.  219;  by  Gery,  in  the 
Melanges  de  Chirurgie  etrangere,  Geneva,  1824,  p.  415;  and  by  Professor  Giu- 
seppe Trasmondi,  in  the  Arcadica  Journal  of  Rome,  vol.  xix.  p.  1,  1823. 


VOL.  II.— 52 


406  NERVOUS  SYSTEM. 


Of  the  Nerves  of  the  Orbit. 

In  addition  to  the  optic  nerve,  there  are  several  belonging  to 
the  eye  and  to  its  auxiliary  parts;  they  are  derived  from  the 
Motor  Oculi  or  third  pair;  from  the  Trochlearis,  or  fourth  pair; 
from  the  first  branch  of  the  Trigeminus,  or  fifth  pair;  and  from 
the  Motor  Oculi  Externus  or  sixth  pair.  For  an  account  of 
which,  see  Nerves. 


Of  the  Arteries  of  the  Orbit. 

The  Eyeball,  and  it§  auxiliary  parts,  are  principally  supplied 
by  the  Ophthalmic  Artery,  which,  as  was  mentioned  in  the  ac- 
count of  the  Brain,  is  a  considerable  branch  given  off  by  the  In- 
ternal Carotid  at  the  fore  part  of  the  Sella  Turcica.  This  branch 
gets  into  the  orbit  on  the  outer  side  of  the  optic  nerve  through 
the  optic  foramen,  and,  after  a  short  course,  crosses  obliquely 
above  the  optic  nerve,  so  as  to  pass  to  the  internal  side  of  the 
orbit.  It  sends  off  a  great  many  small  trunks,  which  are  very 
inconstant  both  in  their  size  and  origin;  they  are  as  follow: — 

1.  Arteria  Lachrymalis  arises,  commonly,  soon  after  the  oph- 
thalmic has  got  into  the  orbit:  it  goes  forwards,  between  therec- 
tus  superior  and  the  rectus  externus  muscle,  to  which  it  dis- 
tributes  arterioles;   it  then   reaches   the  lachrymal  gland,  and 
having  left  branches  with  it,  what  remains  issues  out  at  the  ex- 
ternal angle  of  the  eye,  so  as  to  supply  the  contiguous  part  of 
the  upper  eyelid. 

2.  Arterise  Ciliares.     According  to  Soemmering,  before  the 
prigin  of  the  lachrymal  artery,  the  ophthalmic  detaches  from 
one  to  three  ciliary,  which  penetrate  into  the  ball  of  the  eye 
near  the  optic  nerve.    Other  arteries  of  the  same  class  arise  sub- 
sequently from  the  ophthalmic,  and,  occasionally  some  of  them 
from  the  lachrymal  itself.     They  go  to  the  choroid  coat  of  the 
eyeball  and  to  the  iris. 


THE  EYE.  407 

3.  The  Arteria  Centralis  Retinae  arises  from  among  the  clus- 
ter of  ciliary  arteries,  and,  like  them,  has  no  invariable  root.    It 
penetrates  the  optic  nerve  about  the  middle  of  its  orbitar  por- 
tion, and,  going  in  its  centre,  gets  into  the  eye  through  the  crib- 
riform part  of  the  sclerotica.     It  is  then  distributed  by  ramus- 
cles  to  the  retina,  to  the  tunica  hyaloidea,  and  to  the  capsule  of 
the  lens. 

4.  The  Arteria  Ethmoidea  Posterior  is  inconstant  in  exist- 
ence, and  comes  at  one  time  from  the  trunk,  at  another  from  a 
branch  of  the  ophthalmic.     It  passes  over  the  superior  oblique 
muscle,  and  penetrating  through  the  posterior  orbitary  foramen, 
is  spent  by  arterioles  upon  the  neighbouring  part  of  the  dura 
mater,  and  upon  the  posterior  ethrnoidal  cells,  where  it  anasto- 
moses upon  the  Schneiderian  membrane,  with  branches  from 
the  internal  maxillary. 

5.  Arteriae  Musculares.    Of  these  there  are  two ;  one  of  them* 
the  inferior,  sends   branches  to  the  rectus  interims,  rectus  infe- 
rior, and  obliquus  inferior  oculi;  also  to  the  lachrymal  sac,  and 
to  the  parts  about  the  bottom  of  the  orbit.     It  occasionally  de- 
taches some  of  the  ciliary  arteries.     The  superior  muscular 
branch  is  also  called  the  supra  orbitar.     It  supplies  the  muscles 
of  the  superior  part  of  the  orbit,  and  then  issuing  through  the 
supra  orbitary  foramen,  it  is  spent  in  arterioles,  upon  the  os 
frontis  and  its  periosteum,  and  upon  the  orbicularis  oculi,  cor- 
rugator  supercilii,  and  occipito-frontalis.     It  anastomoses  there 
with  other  branches  of  the  ophthalmic,  and  with  the  temporal 
artery. 

It  is  usual  for  the  anterior  ciliary  arteries  to  come  from  the 
muscular  branches. 

The  Ophthalmic  Artery,  after  having  detached  all  the  afore- 
said branches,  is  much  diminished  in  volume,  and,  advancing 
along  the  internal  parts  of  the  orbit,  its  next  branch  is — 

6.  The  Arteria  Ethmoidea  Anterior,  which  dips  into  the  an- 
terior  internal   orbitary  foramen,    and    is   divided  into  small 
branches,  some  of  which  are  spent  upon  the  adjacent  portion  of 


408  NERVOUS  SYSTEM. 

the  dura  mater,  others  upon  the  frontal  sinus  and  the  anterior 
ethmoidal  cells.  Some  of  these  branches  penetrate  from  the 
cranium  through  the  cribriform  bone  into  the  nose,  and,  rami- 
fying upon  the  Schneiderian  membrane,  anastomose  with  the 
internal  maxillary. 

7.  The  Arterise  Palpebrales  are  two  in  number:  they  come 
sometimes  from  a  common  trunk,  and  on  other  occasions  arise 
separately.  One  is  the  Superior,  and  the  other  the  Inferior. 
The  latter  arises  first,  and  is  distributed  to  the  conjunctiva,  the 
caruncula  lachrymalis,  lachrymal  sac;  and  finishes  by  many 
small  branches  to  the  lower  eyelid,  that  anastomose  with  the 
infra-orbital  artery,  so  as  to  form  the  lower  tarsal  arch.  It 
also  anastomoses  with  the  lachrymal  artery  by  its  extreme 
branches. 

The  Superior  Palpebral  Artery  also  distributes  branches  to 
the  conjunctiva,  sac,  and  caruncle;  it  then  emerges  above  the 
inner  palpebral  ligament,  around  the  margin  of  the  superior  eye- 
lid, and  forms,  along  with  the  lachrymal  and  the  supra  orbital 
artery,  the  superior  tarsal  arch,  which  distributes  small  branches, 
in  great  profusion,  to  the  orbicularis  muscle,  and  to  the  struc- 
ture, generally,  of  the  lid.  It  anastomoses,  externally,  with  the 
lower  palpebral  artery. 

S.  The  Arteria  Nasalis  is  sometimes  a  well  marked  continu- 
ation of  the  ophthalmic.  It  passes  out  of  the  orbit  at  its  inter- 
nal canthus,  above  the  internal  palpebral  ligament,  and  anas- 
tomoses at  the  root  of  the  nose  with  the  facial  artery.  It  is 
distributed  to  the  side  of  the  nose,  and  to  the  lower  part  of 
the  forehead.  Its  chief  contribution  to  the  eyelids  is  at  the  in- 
ternal end  of  the  orbicularis,  where  it  anastomoses  with  the  pal- 
pebral arteries. 

9.  The  Arteria  Frontalis  passes  out  of  the  orbit,  at  the  supra 
orbitary  foramen.  It  is  quickly  divided  into  branches,  which 
go  to  the  orbicularis  and  corrugator  muscles,  to  the  occiplto- 
frontalis,  and  to  the  frontal  sinus. 


THE  EYE.  409 


Of  the  Veins  of  the  Orbit. 

The  blood  distributed  to  the  eyeball  and  to  its  auxiliary  parts> 
has  two  routes  for  returning  to  the  heart,  one  through  the  ca- 
vernous sinus,  and  the  other  by  the  superficial  veins  of  the  face. 
As  a  general  rule,  all  the  branches  of  the  ophthalmic  artery  which 
reach  the  eyelids,  or  become  otherwise  superficial,  return  their 
blood  by  the  latter  route;  and  those  whose  distribution  is  to  the 
ball  of  the  eye  and  to  the  parts  deeply  seated  in  the  orbit,  re- 
turn their  blood  by  the  sinus. 

When  the  veins  are  well  injected,  a  very  considerable  num- 
ber is  manifested  in  both  eyelids.  They  form  a  handsome  net- 
work, the  meshes  of  which  are  small  and  numerous,  and  com- 
mence by  small  roots  at  the  margin  of  the  eyelids.  The  vessels  of 
this  net-work  becoming,  successively,  larger  from  the  centre  to 
the  circumference  of  the  orbicularis,  cover  the  whole  surface  of 
the  latter,  and  from  the  thinness  of  the  skin  are  readily  seen  be- 
neath it.  The  veins  of  the  lower  eyelid  are  discharged  into 
the  facial  vein,  where  it  borders  on  the  orbicularis;  and  the 
veins  of  the  upper  lid,  being  bordered  along  the  superior  mar- 
gin of  the  orbicularis  by  a  horizontal  branch  of  the  temporal 
vein,  discharge  themselves  into  it. 

The  Ophthalmic  Vein  (Sinus  Ophthalmicus]  is  the  large 
trunk  within  the  orbit  which  receives,  successively,  the  remain- 
ing blood  of  the  eye,  and,  passing  along  the  internal  parts  of  the 
orbit,  crosses  over  the  optic  nerve,  and  penetrates  through  the 
optic  foramen  into  the  cavity  of  the  cranium,  where  it  termi- 
nates in  the  cavernous  sinus.  It  may  be  considered  as  com^ 
mencing  by  an  anastomosis  with  the  facial  vein  at  the  internal 
c'anthus;  it  then  receives  the  following  branches: — 

1.  The  nasal,  which  arises  from  the  parts  about  the  internal 
canthus  of  the  eye. 

2.  The  anterior  ethmoidal,  which  comes  from  the  nose  and 
frontal  sinus. 

3.  Branches  from,  the  recti  and  obliqui  muscles. 


410  NERVOUS  SYSTEM. 

4.  The  lachrymal  vein,  from  the  lachrymal  gland  and  leva- 
tor  palpebrae  muscle. 

5.  Posterior  ethmoidal  vein,  from  the  nose. 

6.  The  ciliary  veins,  or  those  of  the  choroid  coat,  which  are 
very  numerous. 

7.  The  central  vein  of  the  retina,  which  is  collected  from 
three  or  four  principal  branches,  and  follows  the  course  of  the 
artery  of  the  same  name,  through  the  cribriform  part  of  the 
sclerotic  coat,  and  through  the  centre  of  the  optic  nerve.     The 
trunks  of  this  vein  anastomose,  at  the  anterior  margin  of  the 
retina,  with  those  of  the  Ciliary  Body. 

There  are,  of  course,  frequent  anastomoses  between  the  veins 
of  the  eyelids  and  the  primitive  branches  of  the  ophthalmic 
vein. 

SECT.   II. OF  THE  BALL  OF  THE  EYE. 

The  Eyeball  (Bulbus  Oculi)  is  situated  within  the  anterior 
half  of  the  orbit,  from  which  it  is  kept  separated  by  its  auxili- 
iary  parts,  and  by  a  large  quantity  of  adipose  matter  which  fills 
up  their  interstices.  It  is  very  nearly  spherical,  but  not  so 
much  so  as  to  prevent  its  antero-posterior  diameter,  which  is 
about  an  inch  long,  from  exceeding  in  measurement  every  other. 
Such,  at  least,  is  the  general  opinion  of  anatomists:  but  from 
some  recent  experiments,  made  by  distending  the  eye  with  mer- 
cury, I  have  been  induced  to  doubt  its  correctness,  and  especial- 
ly in  the  African;  for,  in  the  latter,  I  found  the  transverse  dia- 
meter to  exceed  the  antero-posterior  by  a  line  or  more.  The 
Eyeball  is  also  somewhat  flattened  at  the  insertion  of  each  of 
the  straight  muscles. 

It  is  formed  by  a  series  of  concentric  tunics,  one  investing 
the  other,  and  by  humours  contained  within  those  tunics.  Of 
the  former,  the  Sclerotica  and  the  Cornea  are  external,  the  Cho- 
roidea  and  the  Iris  next,  and  the  Retina  is  internal:  of  the  lat- 
ter, the  Vitreous  Humour  is,  by  far,  the  most  abundant,  and 
constitutes  a  principal  part  of  the  eyeball;  the  Crystalline  Hu- 
mour is  in  front  of  the  vitreous;  and  the  Aqueous  is  placed  be- 
tween the  crystalline  and  the  cornea. 


THE  BALL  OF  THE  EYE.  411 


Tunics,  or  Membranes  of  the  Eyeball. 

The  Sclerotic  Coat  (Tunica  Sclerotica,  Jllbuginea)  forms 
about  five-sixths  of  the  exterior  investment  of  the  eyeball,  the 
remaining  sixth  of  which  is  obtained  from  the  cornea.  At  its 
posterior  part  it  is  joined  by  the  optic  nerve:  this  junction  does 
not  occur  precisely  at  its  axis  or  centre,  but  at  the  inner  side  of 
it.  When  the  optic  nerve  is  detached  at  this  junction,  a  small 
round  hole  is  perceptible  in  the  sclerotica,  or,  rather,  it  is  more 
frequently  perceived  as  a  thin  cribriform  lamella,  through  the 
holes  of  which  the  pulpy  part  of  the  optic  nerve  passes,  so  as 
to  get  within  the  eye.  This  cribriform  lamella,  or  the  appear- 
ance of  it,  is  no  doubt  produced  artificially  by  the  nerve  being 
commonly  cut  through  very  near  the  eye;  and,  as  Mr.  Jacobs, 
of  Dublin,  very  properly  suggests,  should  be  considered  as  the 
most  anterior  termination,  or  the  point  of  the  optic  nerve  in- 
stead of  as  a  portion  of  the  sclerotica.  The  neurileme  of  the 
optic  nerve,  is  so  arranged,  that  small  round  longitudinal  canals 
are  left,  which  contain  the  nervous  matter:  from  this  cause  it 
happens  that  a  thin  section  of  the  optic  nerve  in  any  part  of  its 
course  in  the  orbit,  will,  if  held  up  to  the  light,  manifest  the 
same  cribriform  arrangement  with  the  part  alluded  to.  This 
part  of  the  structure  of  the  optic  nerve  will  be  readily  under- 
stood by  the  American  student,  in  comparing  it  with  the  pith 
of  the  Indian  corn-stalk,  which,  being  traversed  longitudinally, 
by  many  fibres,  upon  the  drawing  of  them  out,  an  equal  num- 
ber of  longitudinal  canals  is  left  in  their  places. 

At  its  fore  part,  the  edge  of  the  sclerotica  is  bevelled  all 
around  for  its  junction  with  the  cornea;  and  though  nearly  cir- 
cular, is  not  completely  so,  from  its  horizontal  diameter  being 
vsomewhat  greater  than  any  other.  There  are  several  orifices 
of  inconsiderable  size  scattered  over  the  sclerotica,  some  of 
which  are  oblique  and  others  direct:  they  transmit  the  blood 
vessels  and  nerves.  The  Sclerotica  is  nearly  a  line  in  thick- 
ness at  its  back  part,  from  which  it  gradually  becomes  reduced 
to  half  that  thickness  in  front,  where  it  is  strengthened  by  the 
tendinous  insertions  of  the  recti  muscles.  Its  internal  surface 


412  NERVOUS  SYSTEM. 

is  smooth  and  somewhat  shining,  being  loosely  attached  to  the 
cellular  substance  intervening  between  it  and  the  choroid  coat; 
but  the  external  surface  is  rough,  and  more  obviously  fibrous, 
and  is  attached  somewhat  strongly  to  all  the  adjoining  parts. 

This  membrane  is  of  a  white  colour,  and  consists  of  a  single 
layer,  whose  structure  is  essentially  fibrous.  The  fibres  are 
very  closely  compacted,  and  compose  an  intertexture  which  can- 
not be  unravelled.  It  is  so  closely  united  to  the  dura  mater  co- 
vering of  the  optic  nerve,  that  many  anatomists,  notwithstand- 
ing its  greater  thickness,  are  disposed  to  speak  of  it  as  a  conti- 
nuation of  the  same.  Its  strength  and  its  want  of  elasticity  suit 
it  remarkably  to  maintain  the  form  of  the  eye,  and  to  resist  in- 
juries. Out  of  the  many  blood  vessels  that  penetrate  it,  but 
few  ramify  in  its  structure,  and  the  existence  of  nerves  in  it  is 
by  no  means  evident. 

The  tunica  arachnoidea  follows  the  course  of  the  optic  nerve, 
within  its  coat  of  dura  mater,  and  forms,  in  the  eye,  just  around 
the  cribriform  plate,  or  foramen  of  the  sclerotica,  a  circular  pad: 
it  is  then  reflected  on  the  internal  face  of  the  sclerotica,  as 
far  as  its  anterior  edge.  It  is  this  which  causes  the  inter- 
nal face  of  the  sclerotica  to  be  smooth  and  shining,  and  there- 
by to  correspond  with  that  of  the  dura  master.*  This  circum- 
stance is  more  readily  proved  in  a  very  young  eye,  than  in 
the  adult  one. 

The  Cornea,  as  mentioned,  fills  up  the  aperture  at  the  fore 
part  of  the  sclerotica,  and,  of  course,  has  the  same  diameters, 
measuring  thereby  more  transversely  than  in  any  other  direc- 
tion. It  is  a  segment  of  a  smaller  sphere  than  the  sclerotica, 
and  is,  consequently,  more  convex  than  it.  Its  thickness  is 
uniform,  and  commonly  exceeds  that  of  the  sclerotica  at  the 
fore  part  of  the  latter. 

Its  circumference  adheres  very  closely  to  the  sclerotica,  and 
presents  a  bevelled  or  oblique  edge,  which  is  inserted  into  the 
corresponding  bevel  of  the  sclerotica,  so  that  the  latter  includes 
the  former.  The  closeness  of  this  junction  induced  the  older 
anatomists  to  consider  these  membranes  as  one  and  the  same, 

*  J.  F.  Meckel.  Zinn  supposed  this  surface  to  be  derived  from  the  pia  ma- 
ter. 


THE  BALL  OF  THE  EYE.  418 

notwithstanding  their  obvious  difference  of  structure  and  of  pro- 
perties. Their  adhesion  yields  to  protracted  maceration.  The 
cornea  is  covered  in  front  by  a  continuation  of  the  tunica  con- 
junctiva, which  unites  the  eyeball  to  the  eyelids.  This  may  be 
proved  by  dissection,  by  maceration,  and  by  its  sloughing  off 
entirely  along  with  the  epidermis  of  animals  that  are  subject  to 
this  process,  as  the  locust,  snakes,  and  others.  On  its  posterior 
face,  it  is  covered  by  the  membrane  of  the  aqueous  humour, 
which  may  be  rendered  evident  by  steeping  it  in  spirits  of  wine; 
whereby  the  latter  membrane  is  made  more  hard,  and  may  be 
torn  off. 

The  cornea,  in  a  natural  state,  is  perfectly  transparent,  and 
readily  transmits  the  rays  of  light.  It  consists  of  an  indefi- 
nite number  of  laminae,  which  are  placed  one  againt  the  other 
like  the  leaves  of  a  book,  and  are  united  by  a  delicate  trans- 
parent cellular  substance  which  permits  the  laminae  to  slide 
upon  each  other.  These  laminsa  are  kept  moist  and  pellucid 
by  an  interstitial  secretion  of  a  fluid  equally  pellucid  with  them- 
selves, the  abundance  of  which  in  health  gives  to  the  eye  its 
brilliancy,  and  the  deficiency  of  it  in  illness  and  in  death  causes 
the  eye  to  look  dim  and  somewhat  opaque.  Its  evaporation, 
which  no  doubt  is  continually  occurring,  is  as  constantly  sup- 
plied by  a  fresh  and  abundant  secretion.  The  motion  of  the 
eyelids  sweeps  the  residuum,  after  the  evaporation  of  its  wa- 
tery particles,  from  the  surface  of  the  cornea:  without  this  pro- 
cess, the  residuum  appears  as  a  thin  layer  or  film  of  albuminous 
matter  spread  over  the  cornea,  when  the  eye  is  kept  open 
without  winking  for  a  considerable  time. 

The  cornea  has  not  the  fibrous  structure  of  the  sclerotica, 
yet  the  application  of  mechanical  force  to  the  eyeball  shows 
that  it  is  stronger.  Neither  has  it  vessels,  conveying  red  blood 
naturally,  yet,  in  a  state  of  inflammation,  its  capillaries  dilate 
so  as  to  admit  red  blood,  and  deposite  coagulating  lymph  be- 
tween its  layers.  It  is  common  for  anatomists  to  attribute  a 
want  of  sensibility  to  it  in  a  natural  state:  as  a  general  rule, 
this  is  fallacious;  for  many  persons,  where  the  eyes  are  not  in- 
flamed, suffer  extremely  from  its  being  cut  in  cataract,  and  some- 
times faint  from  the  pain,  while  others  are  truly  unconscious  of 
the  incisions  made  through  it.  Of  this  opinion,  I  have  a  full 
VOL.  II.— 53 


414  NERVOUS  SYSTEM. 

assurance  from  repeated  observations  on  the  practice  of  Dr. 
Physick,  as  well  as  in  instances  in  my  own  hands. 

The  Choroid  Coat  (Tunica  Choroidea,  Vasculosa^  is  placed 
immediately  within  the  circumference  of  the  sclerotica,  and  is 
of  equal  extent  At  its  posterior  part  it  furnishes,  for  the  pas- 
sage of  the  optic  nerve,  a  singular  annular  opening,  the  margin 
of  which  is  somewhat  thickened,  and  perfectly  distinct  from 
the  pia  mater  investment  of  the  nerve,  from  which  some  anato- 
mists have  desired  to  trace  this  coat.  The  anterior  opening 
of  the  choroid  is  bounded  by  the  ciliary  ligament  and  by  the 
iris.  On  its  outer  side  may  be  seen  an  abundance  of  loose 
flocculent  cellular  substance  which  joins  it  to  the  sclerotica. 
Internally,  it  is  spread  over  the  retina,  but  does  not  adhere 
to  it. 

The  choroid  coat  is  closely  fastened,  at  its  anterior  margin, 
to  the  corresponding  part  of  the  sclerotica,  by  a  ring  which 
surrounds  it,  of  a  short  compact  cellular  tissue.  This  ring, 
called  the  Ciliary  Ligament,  (Ligamentum  Ciliare,  Orbiculus 
Ciliaris,)  is  from  a  line  to  two  lines  in  breadth,  and  may  be 
readily  distinguished  by  its  whiteness,  contrasted  with  the  dark 
colour  of  the  choroid.  It  is  intimately  united  to  the  latter,  and 
seems  to  form  a  part  of  its  structure,  whereby  it  is  caused  to 
detach  itself  entirely  from  the  sclerotica,  and  to  adhere,  by  pre- 
ference, to  the  choroid  when  these  two  membranes  are  sepa- 
rated.* The  iris  is  set  in  the  front  margin  of  the  ciliary  liga- 
ment, so  that  the  sclerotica  and  the  cornea  may  be  peeled  from 
the  choroidea  and  iris,  without  impairing  the  continuity  of  the 
two  latter.  Just  beyond  the  junction  of  the  two  last,  the  liga- 
ment presents  a  small  ridge  or  elevation  all  around,  which  is 
fitted  into  a  corresponding  fossa  at  the  circumference  of  the 
posterior  face  of  the  cornea. 

The  internal  face  of  the  choroid  coat,  as  well  as  its  anterior 
margin,  undergo  a  very  remarkable  change  from  the  general 
plan  of  this  tunic,  by  forming  what  is  called  the  Ciliary  Body, 
(Corpus  Ciliare,  Corona  Ciliaris.)  In  order  to  see  this  in 

*  Fontana  asserted  that  a  circular  canal  was  to  be  found  in  this  ligament; 
rnanv  examiners  have  failed  in  finding  it,  and  its  existence  is  denied. 


THE  BALL  OP  THE  EYE. 


415 


the  most  favourable  manner,  the  eye  should  be  laid  on  the  cor- 
nea, and  its  posterior  half  cut  away.  It  will  then  be  evident, 
that  just  behind  the  iris,  and  within  the  circumference  of  the 
ciliary  ligament,  the  internal  face  of  the  choroid  coat  forms  a 
considerable  number  of  radiated  folds  or  little  ridges,  which 
converge  from  behind  forwards  and  inwards.  These  folds 
commence  by  striae,  almost  imperceptible  to  the  naked  eye, 
which  are  in  contact  with  the  fore  part  of  the  vitreous  humour, 
and  with  the  canal  of  Petit,  and  thereby  not  only  impress  the 
neighbouring  portion  of  the  tunica  hyaloidea  with  their  shape, 
but  evd&n  leave  upon  it  the  black  pigment  with  which  they 
themselves  are  covered.  These  folds,  when  they  get  near  the 
circumference  of  the  iris,  coalesce  one  with  another,  and  ter- 
minate in  a  considerable  number  (from  fifty  to  sixty,  accord- 
ing to  Soemmering,)  of  processes,  (Processus  Ciliares,)  the 
central  extremities  of  which  are  loose,  and  float  in  the  aqueous 
-  humour.  Some  of  these  processes  are  longer  than  others.  As 
a  whole,  the  ciliary  processes  constitute  a  ring  of  radiating  fila- 
ments, which  are  a  line  or  more  in  length,  placed  along  side  of, 
and  in  contact  with,  one  another;  the  external  periphery  of  the 
ring  adheres  to  tjie  ciliary  ligament,  and  through  it  to  the  greater 
circumference  of  the  iris,  so  that  the  ring  appears,  but  falla- 
ciously, to  be  continuous  with  the  iris.  In  certain  animals,  as 
the  sheep,  the  radiated  appearance  of  the  iris,  on  its  posterior 
face,  favours  this  notion  still  more.  The  internal  periphery  of 
the  ring  presents  the  central  ends  of  the  filaments  detached 
from  one  another,  and  of  a  downy  appearance;  with  the  handle 
of  a  knife  they  may  be  readily  pushed  backwards  and  forwards. 
Generally  speaking,  the  ciliary  processes  are  so  much  con- 
cealed by  the  iris,  that  they  cannot  be  seen  in  the  living  body 
through  the  cornea:  in  cases,  however,  of  extreme  dilatation  of 
the  pupil  by  narcotic  applications,  their  central  extremities  are 
brought  into  view. 

The  choroid  coat  always  appears,  when  uninjected,  of  a  very 
dark  brown  or  black  colour,  arising  from  a  black  paint  (Pig- 
mentum  Nigrum)  being  very  thickly  spread  over  the  whole 
of  that  surface  of  it  which  is  adjacent  to  the  retina,  and  being 
also  diffused  through  its  thickness.  This  paint  is  more  abun- 
dant near  the  iris  than  posteriorly,  being  laid  on  there  in  flakes, 


416  NERVOUS  SYSTEM. 

in  the  intervals  between  the  ciliary  striae,  and  tinging  also  the 
ciliary  processes.  It  may  be  removed  in  a  considerable  degree, 
indeed  almost  entirely,  by  maceration,  or  by  careful  washing 
with  a  camel's-hair  pencil.  It  is  supposed  to  be  an  exhalation 
from  the  vessels.  Its  particular  colour  is  of  a  most  durable 
kind.  According  to  the  observations  of  Bichat,  the  long-con- 
tinued action  of  light  upon  it,  when  this  pigment  is  transferred 
from  the  choroid  to  a  piece  of  paper,  does  not  affect  it;  neither 
is  it  changed  by  being  submitted  to  very  strong  chemical  agents, 
as  sulphuric,  muriatic,  or  nitric  acid,  alcohol,  or  caustic  potash. 
This  degree  of  indestructibility  of  colour  is  an  invaluable  pro- 
perty, and  almost  singular;  for  it  is  well  known  to  the  keepers 
of  medicinal  articles,  that  the  colours  of  all  of  them  yield  to  the 
continued  influence  of  light,  and  that  they  also  become  weaker 
by  the  same  cause. 

In  regard  to  structure,  the  choroid  coat  is  thin,  soft,  and  easily 
lacerated:  when  cleared  of  its  pigment  by  maceration,  it  is  semi- 
transparent,  and  is  then  seen  evidently  to  consist  of  but  one  la- 
mina; unless  we  may  be  disposed  to  consider  as  a  second  one 
the  pigment,  naturally  on  its  internal  face.  It  has  no  appear- 
ance of  fibres  in  its  composition,  but,  when  injected,  seems  to 
consist  almost  wholly  of  arteries  and  of  veins. 

The  arteries  are  branches  of  the  ophthalmic,  and  are  called 
ciliary.  There  are  two  Long  Ciliary  Arteries,  which  pene- 
trate the  sclerotic  coat  not  far  from  the  optic  nerve,  and  pass, 
one  of  them,  on  the  external  and  superior  part  of  the  choroides, 
and  the  other  on  its  inferior  and  nasal  side,  to  the  front  of  the 
eye.  In  this  course,  they  do  not  send  off  any  branches  of  con- 
sequence till  they  reach  the  iris,  on  which  they  are  distributed. 
The  Short  Ciliary  Arteries  are  much  more  numerous  than  the 
others,  and  also  smaller;  their  number  sometimes  amounts  to 
twenty;  the  most  of  them  penetrate  the  sclerotica  from  behind, 
near  the  optic  nerve  also.*  They  quickly  divide  into  a  great 
number  of  branches,  which  depart  at  very  acute  angles,  and 
have  frequent  anastomoses  with  one  another.  These  branches 
run  forwards,  nearly  parallel,  and,  at  the  fore  part  of  the  cho- 

*  Soemmering,  Icones  Oculi  Hiunani. 


THE  BALL  OF  THE  EYE.  417 

roides,  form  a  very  intricate  intertexture,  which  is  continued 
upon  the  ciliary  processes,  and  communicates  with  the  vessels 
of  the  iris.* 

The  veins  of  the  choroid  coat  are  also  extremely  abundant. 
They  run  from  before  backwards,  and  the  branches  which  con- 
cur to  form  them,  being  adjacent  with,  and  parallel  to  each  other, 
for  the  most  part,  form  large  curves,  the  convexity  of  which  is. 
for  wards  j  they,  moreover,  anastomose  freely,  and  thereby  pro- 
duce a  vascular  sort  of  net-work,  filling  up  the  concavity  of  some 
of  the  curves.  These  veins,  called  the  Vasa  Vorticosa,  are 
nearer  the  external  surface  of  the  choroides  than  the  arteries, 
and  are  assembled  into  twelve  or  fourteen  trunks,  which,  en- 
gaging in  the  sclerotica,  near  its  middle,  run  for  some  distance 
in  its  substance,  and  then,  by  their  junction,  are  reduced  to  four 
or  five  in  number.  The  latter,  disengaging  themselves  from 
the  eye,  join,  subsequently,  the  ophthalmic  vein. 

In  addition  to  the  veins  mentioned,  the  long  ciliary  arteries 
have  their  venae  comites,  which  take  a  course  parallel  to  and  ad- 
joining them.  These  veins  do  not  observe  the  vortical  arrange- 
ment of  the  others;  they  bring  back  the  blood  of  the  iris,  and 
terminate  in  the  larger  trunks  of  the  others. 

This  structure  has  been  most  cautiously  explored  by  the  ce- 
lebrated Soemmering,  and  his  observations  have  tended  very 
much  to  determine  the  opinions  of  anatomists  concerning  many 
parts  of  the  eye.  A  curious  remark  of  his  is,  that  "  the  human 
eye  may  be  distinguished  from  that  of  animals  by  a  form  of  this 
vascular  net- work,  entirely  peculiar;  for  example,  in  the  eye  of 
the  ape,  its  vascular  tissue  differs  not  only  from  that  of  the  hu- 
man subject,  but  also  from  that  of  the  dog,  and  still  more  evi- 
dently from  that  of  the  calf.  From  which  cause,  it  would  be  as 
easy  to  distinguish  with  a  microscope,  the  choroides,  well  in- 
jected, of  different  animals,  even  a  piece  of  only  the  forty- 
eighth  part  of  an  inch  in  extent,  as  it  is  easy  to  distinguish  a 
poplar  stripped  of  its  leaves  from  an  oak,  a  pear  tree,  an  apple 
tree,  or  any  other  tree,  by  the  arrangement  of  its  trunk  and 
branches." 

*  Icones  Oculi  Humani. 


418  NERVOUS  SYSTEM. 

The  choroides,  on  its  internal  face,  is  not  smooth,  but  velvety, 
which  becomes  still  more  conspicuous  when  the  eye  is  finely 
injected  and  examined  with  a  microscope.  Meckel  considers 
the  appearance  to  depend  upon  its  very  fine  tissue  of  vessels. 
This  surface  is  called  Tapetum,  in  the  bullock,  and  some  other 
animals,  at  a  particular  part,  it  presents  a  shining,  silvery  ap- 
pearance, and  may  be  torn  off  from  the  external  surface. 
Ruysch  attributed  two  laminae  to  the  membrane  in  the  human 
subject,  the  internal  of  which  was  called  after  his  name,  but  the 
distinction  is  now  generally  abandoned. 

The  Iris  is  a  circular  plane  placed  at  the  front  of  the  cho- 
roides,  and  having,  in  its  centre,  a  round  opening  called  the  pu- 
pil (jpupilla^  Its  external  circumference  is  attached  to  the  ci- 
liary ligament,  and  by  it  to  the  choroid  coat,  and  is  exactly  at 
the  junction  of  the  cornea  with  the  sclerotica.  Professor  Sum- 
mering has  bestowed  much  attention  in  ascertaining  whether 
this  membrane  is  perfectly  flat  or  somewhat  convex  in  front, 
and,  by  repeated  observations,  carefully  made,  has  assured  him 
self  that  it  is  flat*  My  own  observations  and  preparations  have 
induced  me  to  believe  that  in  many  cases  it  will  be  found  slight- 
ly convex  in  front,  as  Petit  asserted  more  than  a  century  ago. 
In  a  moderate  state  of  dilatation,  its  nasal  or  internal  border 
is  somewhat  narrower  than  its  external  or  temporal.  With  the 
exception  of  its  external  circumference,  every  part  of  the  iris  is 
free  from  any  attachment;  by  which  arrangement  it  moves  free- 
ly in  the  aqueous  humour,  so  as  to  contract  or  dilate  its  pupil, 
according  to  the  quantity  of  light  admitted  upon  the  eye. 

The  iris,  with  the  exception  of  its  central  or  pupillary  cir- 
cumference, where  it  is  thinner  than  elsewhere,  is  much  thick- 
er than  the  choroid  coat.  The  posterior  face  of  the  iris,  some- 
times called  uvea,  is  covered  in  great  abundance  with  pigmen- 
tum  nigrum.  When  this  is  removed  by  maceration,  which  may 
be  readily  done,  the  membrane  becomes  semi-transparent.  Its 
anterior  surface  is  the  seat  of  the  colour,  which  characterizes 
every  individual's  eyes.  There  are  but  two  of  these  colours, 
light  blue  and  orange,  the  predominance  of  one  or  the  other  of 

*  Icones  Oculi  Hutnani. 


THE  BALL  OP  THE  EYE.  419 

which,  assisted  by  the  dark  ground  on  the  back  of  the  iris,  gives 
the  cast  of  hue  to  the  eye.  The  front  surface,  when  examined 
on  the  living  eye  with  the  microscope,  is  seen  to  be  downy  or 
flocculent,  and  is  traversed  by  filaments  forming  an  intertex- 
ture,  some  of  which  are  circular,  others  oblique;  and  others  ra- 
diated. This  arrangement  is  remarkably  distinct  in  the  eye  of 
the  seal.  % 

The  power  which  the  iris  has  of  dilating  the  pupil  when  there 
is  but  little  light,  and  of  contracting  it  when  there  is  much, 
has  induced  many  anatomists  to  think  that  it  is  formed  of  mus- 
cular radiated  fibres,  which  by  their  contraction  produce  the  first 
motion,  and  of  circular  ones  which  produce  the  last.  Among 
these  anatomists  may  be  mentioned,  Ruysch,  Morgagni,  Zinn, 
Sabatier.  Ruysch  asserted  that  the  radiated  fibres  extended 
from  the  greater  circumference  of  the  iris  to  the  pupil,  and  were 
fixed  there  by  very  delicate  tendons.  The  late  Doctor  Monro, 
of  Edinburgh,  has  described  particularly  the  circular  fibres,  and 
a  preparation  of  the  bullock's  eye  which  belonged  to  him  is  still 
exhibited  there,  where  these  fibres  are  seen  around  the  margin 
of  the  pupil.  The  several  fibres  can  only  be  seen  distinctly,  when 
the  pigmentum  nigrum  is  washed  away.  Demours  and  Meckel 
deny  the  existence  of  the  radiated  fibres.  The  late  distinguished 
Professor  Wistar  taught  that  the  contraction  of  the  pupil  was 
produced  by  circular  fibres,  and  the  dilatation  of  it  by  its  elas- 
ticity. In  objection  to  this,  Dr.  Physick  remarks,  that  as  elas- 
ticity is  as  much  a  property  of  dead  as  of  living  matter;  in  death, 
therefore,  we  should  always  find  the  pupil  dilated  from  the  want 
of  active  contraction  in  the  circular  fibres;  also,  in  cases  of  con- 
cussion of  the  brain,  where  there  is  a  sudden  loss  of  sensibility 
and  of  muscular  motion,  the  pupil  should  be  invariably  dilated; 
but  the  fact  is,  that  the  pupil  remains  just  in  the  same  state  that 
it  was  at  the  moment  of  the  accident* 

Notwithstanding  the  extreme  sensibility  and  mobility  of  the 
iris  on  the  admission  of  light,  one  is  occasionally  astonished  to 
find  it  not  contracting  when  instruments  are  applied  to  it,  as  I 

*  It  would  appear  that  the  question  of  the  muscularity  of  the  iris  has  been 
settled  almost  conclusively  by  Mr.  Bauer.  See  Ph.  Trans,  for  1822. 


420  NERVOUS  SYSTEM. 

have  had  an  opportunity  of  twice  observing,  upon  the  removal 
of  a  considerable  portion  of  it,  in  making  an  artificial  pupil  for 
opacity  of  the  cornea.  In  these  cases,  upon  the  letting  out  of 
the  aqueous  humour,  it  became  quite  as  flaccid  as  we  are  accus- 
tomed to  see  it  in  our  dissections.  The  same  remark  has  been 
made  by  Mr.  now  Sir  Charles  Bell. 

The  Blood  Vessels  of  the  Iris  are  principally  branches  of  the 
Long  Ciliary,  which  have  been  alluded  to.  Each  of  the  two 
J^ong  Ciliary  Arteries  having  gained  the  greater  circumference  of 
the  iris,  bifurcates;  the  bifurcations  run  along  this  circumference, 
meet,  and  join  with  the  corresponding  ones  of  the  other  arterial 
trunk.  From  the  circle  thus  formed  there  proceed  radiated 
branches,  that  run  towards  the  pupil,  and  form  around  its  mar- 
gin, by  their  frequent  anastomoses,  a  fine  vascular  net-work. 
The  radiated  branches  themselves  give  off  collateral  branches, 
which  supply  the  intermediate  spaces  of  the  iris.*  The  veins 
of  the  iris  are  also  numerous,  but  cannot  be  quite  so  distinctly 
seen:  they  enter  into  the  long  ciliary  veins,  and  also  into  the 
vasa  vorticosa. 

The  nerves  of  the  Iris  belong,  in  part,  also  to  the  choroid  coat, 
and  are  classed  under  the  term  Ciliary,  (Nervi  Ciliares.)  They 
arise  from  the  ophthalmic  ganglion,  and  from  the  trunks  contri- 
buting thereto,  and  are  about  twenty  in  number.  They  penetrate 
the  posterior  part  of  the  sclerotica  obliquely,  and  then  run  for- 
wards between  it  and  the  choroides.  Having  reached  the  pos- 
terior part  of  the  ciliary  ligament,  they  penetrate  it,  and  distri- 
bute their  filaments  in  its  substance,  after  the  same  fashion 
that  the  trigeminus  nerve  is  divided  in  its  glanglion.  This  cir- 
cumstance has  given  occasion  to  Soemmering  to  consider  the 
ligament  as  a  true  ganglion,  and  to  call  it  Annulus  Gangliformis. 
The  nerves  then  get  to  the  front  of  the  iris,  and  are  there  dis- 
tributed as  white  radiating  filaments;  in  the  course  of  which  may 
be  observed  small  nodes,  supposed  by  Meckel  to  be  Ganglions. 

The  trunks  of  the  ciliary  nerves  depart  from  the  common 
form  of  such  bodies,  by  being  flattened  instead  of  cylindrical: 
they  are  small,  and  resemble  sewing  threads.  From  their  num- 
ber, the  iris  is  probably  more  abundantly  supplied  with  nerves 
than  any  other  organ  of  the  body. 

*  Soemmering,  Icones  Oculi  Humani. 


THE  BALL  OF  THE  EYE.  421 

The  Retina  forms  the  third  coat  of  the  eye,  and  lines  the  in- 
ternal face  of  the  choroides  almost  in  its  whole  extent.  The 
optic  nerve  having  passed  through  the  selerotica,  terminates  on 
its  inner  side  by  a  bulb  or  button-like  end,  from  the  circumfe- 
rence of  which  the  retina  begins  to  expand,  and  may  be  traced 
satisfactorily  as  far  as  the  commencement  of  the  ciliary  plaits  of 
the  choroid  coat,  where  it  terminates  by  a  straight  edge,  some- 
what thickened.  Just  at  the  edge,  the  retina  adheres  to  the 
vitreous  humour,  and  is  supposed,  erroneously  by  some  anato- 
mists, as  Bichat  and  Monro,  ta  be  continued  on  to  the  circum- 
ference of  the  lens.  Repeated  dissections,  and  the  substantial 
testimony  of  Soemmering,*  have  satisfied  me  that  the  retina 
cannot  be  fairly  traced  beyond  the  greater  circumference  of  the 
impressions  made  on  the  vitreous  humour  by  the  ciliary  striae 
of  the  Choroidea.  When  the  eye  is  slightly  macerated,  the  re- 
tina always  parts  from  the  vitreous  humour  at  this  line;  more- 
over, when  its  structure  is  still  more  slightly  changed  by 
freezing  and  then  thawing,  the  retina  manifests  a  decided  pre- 
ference to  separate  there,  and,  under  the  most  careful  dissec- 
tion, it  is  very  difficult  to  prevent  it.  In  addition  to  these  con- 
siderations, these  is  a  well  marked  change  of  colour  at  the  line 
mentioned:  in  front  of  this  line,  the  surface  is  transparent  when 
cleaned  from  thepigmentum  nigrum;  whereas,  if  it  were  retina, 
it  should  be  the  colour  of  ground  glass,  as  is  usual  in  the  dead 
body:  also  the  veins  of  the  retina  never  trespass  beyond  this 
line,  but  are  seen  to  cruise  along  it. 

Most  anatomists  teach  that  the  retina  is  an  expansion  of  the 
optic  nerve.  Bichat  believed  that  the  latter  terminated  at  the 
bulb,  and  that  the  retina  was  another  part  of  the  structure,  but 
still  consisting  of  the  same  sort  of  nervous  matter.  The  latter 
opinion  is  probably  the  more  strictly  correct,  because  there  is 
more  pulpy  matter  in  a  section  of  the  retina  than-  can  be  found 
in  the  same  length  of  the  optic  nerve;  also,  if  the  retina  were 
simply  an  expansion  of  the  nerve  without  any  addition  of  mat- 
ter to  it,  it  should,  from  its  hollow  globular  shape,  be  thinner 
in  the  middle,  where  it  is  most  expanded,  than  it  is  where  the 
expansion  first  begins  at  the  bulb  of  the  optic  nerve. 

•  *  Icones  Oculi  Human!. 
VOL.  II.— 54 


422  NERVOUS  SYSTEM. 

The  retina  does  not  adhere  to  the  choroid  coat,  neither  to  the 
vitreous  humour  which  it  encloses,  except  at  the  line  mentioned: 
when  this  line  of  attachment  is  broken,  the  retina  quickly  col- 
lapses. 

The  texture  of  the  retina  is  extremely  soft  and  pulpy;  in  the 
living  state,  it  is  probably  perfectly  transparent,  but  this  can 
only  be  conjectured  from  the  readiness  with  which  the  vessels 
of  the  choroid  coat  can  be  seen  in  animals  destitute  of  pigmen- 
tum  nigrum.  It  is  composed  of  two  laminse,  of  which  the  ex- 
ternal is  medullary,  and  the  internal,  or  that  next  to  the  vitre- 
ous humour,  is  formed  of  a  fine  reticulated  cellular  membrane 
with  blood  vessels  running  through  it.  The  external  lamina 
may  be  removed  by  a  camel's  hair-pencil,  or  by  slight  putrefac- 
tion and  washing,  so  as  to  leave  the  internal  entire.  The  cele- 
brated John  Hunter  succeeded,  however,  in  separating  the  two 
laminae  fairly  from  each  other,  and  preserving  them,  so  as 
to  show  their  difference.  This  specimen  may  be  considered 
unique,  and  every  way  deserving  of  the  source  from  which  it 
proceeded.*  t 

Exactly  in  the  axis  of  the  eye,  or  at  its  centre,  posteriorly, 
consequently,  about  a  line  and  a  half  from  the  outer  side  of  the 
bulb  of  the  optic  nerve,  Soemmering  discovered,  in  1791,  a 
yellow  spot  of  a  line  in  diameter,  with  a  small  hole  in  its  middle, 
made  by  a  deficiency  of  medullary  matter.  From  the  optic 
nerve  there  goes,  towards  the  foramen,  a  small-fold  of  the  retina, 
pointed  at  its  internal  end,  and  obtuse  or  bifurcated  externally. 
Unless  the  eye  be  fresh,  these  things  cannot  be  seen  distinctly, 
for  the  evaporation  of  the  aqueous  humour  causes  a  collapse  or 
wrinkling  of  the  retina,  which  obscures  them.  But,  in  a  per- 
fectly fresh  eye,  which  is  well  managed,  they  may  be  seen 
both  from  before  and  behind.  It  was  thought,  for  some  time, 
that  the  yellow  spot  and  the  foramen  were  peculiar  attributes 
of  the  human  being:  more  extended  and  successful  observation 
has  corrected  this  mistake,  by  detecting  them  in  several  classes 
of  animals. 

In  the  centre  of  the  optic  nerve,  where  it  enters  the  eye,  is 

*  The  fact  was  communicated  to  me  by  Dr.  Physick,  who  studied  under  Mr. 
Hunter,  and  frequently  saw  the  preparation. 


THE  BALL  OP  THE  EYE.  423 

a  foramen  for  the  passage  of  the  artery  and  vein  belonging  to 
the  retina.  These  vessels  ramify,  by  a  few  branches,  on  the 
internal  surface  of  the  membrane,  and  form  a  sort  of  circle  sur- 
rounding the  yellow  spot.  Neither  the  branches  of  the  ar- 
teries nor  of  the  veins  communicate  with  those  of  the  cho- 
roides;  and,  as  observed,  never  go  beyond  what  we  just  con- 
sidered as  the  anterior  margin  of  the 'retina,  but  rather  run 
along  it. 

Interposed  between  the  retina  and  the  choroides,  is  a  most 
delicate  serous  membrane,  lately  discovered  by  Mr.  Jacobs, 
Demonstrator  of  Anatomy  in  Trinity  College,  Dublin.  By 
preparing  the  retina  in  the  usual  way,  and  then  floating  the 
eye  in  a  saucer  of  water,  this  membrane  may  be  turned  down 
with  the  handle  of  a  knife  from  the  optic  nerve  to  the  termi- 
nation of  the  retina.  It  is  supposed  to  be  the  seat  of  the  ossi- 
fications which  are  sometimes  met  with  in  the  eye. 

Humours  of  t he,  Eyeball. 

The  Vitreous  Humour  (Humor  Vitreus,  Corpus  Vitreum,} 
occupies,  with  the  exception  of  a  very  small  part  just  behind 
the  iris,  the  whole  of  the  space  posterior  to  the  latter.  It  is, 
therefore,  very  nearly  globular;  is  in  contact  the  greater  part 
of  its  extent  with  the  retina,  at  least  as  far  as  the  latter  mem- 
brane proceeds;  in  front  it  is  in  contact  with  the  crystalline 
humous^  and  from  the  margin  of  the  retina  to  the  circumference 
of  the  lens  it  is  in  contact  with  the  ciliary  body,  meaning  there- 
by the  ciliary  striae  and  processes  of  the  choroides. 

Two  parts  compose  the  vitreous  humour, — the  hyaloid  mem- 
brane and  a  thin  fluid.  In  a  natural  state  they  are  perfectly 
transparent,  and,  therefore,  cannot  be  readily  distinguished 
from  each  other;  but  by  immersion  in  spirits  of  wine  the  mem- 
branous portion  is  brought  to  the  colour  of  ground  glass,  and 
may  then  be  studied  very  advantageously.  The  membrane, 
though  extremely  delicate,  is  generally  strong  enough  to  permit 
the  whole  vitreous  body  to  be  suspended  in  the  air  by  a  thread 
passed  through  it,. and  it  may  also  be  momentarily  held  up  with, 
a  pair  of  forceps. 


424  NERVOUS  SYSTEM. 

The  Tunica  Hyaloidea  may  be  traced  as  a  complete  capsule, 
forming  the  periphery  of  the  vitreous  humour;  and  from  the 
internal  face  of  this  capsule  there  proceeds  a  great  number  of 
partitions  dividing  the  whole  cavity  into  cells  of  various  mag- 
nitudes and  forms.  Some  anatomists,  who  have  frozen  the  eye, 
and  then  picked  out  the  pieces  of  ice  from  the  cells,  have  got 
the  idea  of  their  being  all  cuneiform,  and  of  their  edges  pointing 
forwards.  Our  preparations  in  the  anatomical  cabinet  are  per- 
fectly satisfactory  in  exhibiting  the  existence  of  an  arrange- 
ment of  cells,  but  do  not  manifest  a  regular  cuneiform  shape  in 
them. 

When  the  capsule  of  the  tunica  hyaloidea  has  got  to  the  dis- 
tance of  two  lines,  or  thereabouts,  from  the  circumference  of 
the  lens,  it  divides  into  two  laminae,  which  reunite  at  the  cir- 
cumference of  the  lens.  They  then  divide  again,  and  one  goes 
before  the  capsule  of  the  lens,  and  the  other  behind  it.  The 
space  between  the  two  layers,  around  the  circumference  of  the 
lens,  is  the  canal  of  Petit,  and  is  that  part  of  the  tunica  hya- 
loidea which  is  impressed  by  the  ciliary  striae  and  ridges  of  the 
choroides.  At  intervals,  passing  in  a  radiated  manner  from 
the  exterior  to  the  interior  circumference  of  the  canal,  there  is 
a  sort  of  shortening  or  constriction  of  it,  producing  partial 
septa  in  its  cavity;  so  that  when  the  canal  is  inflated,  it  seems 
to  consist  of  a  series  of  small  cells,  arranged  circularly.  The 
cells  of  the  colon  will  give  some  idea  of  this  arrangement,  though 
ttajy  are  produced  in  an  entirely  different  manner. 

The  fluid  part  of  the  vitreous  humour,  by  analysis,  gives  out 
9S.40  water,  .16  albumen,  and  the  remainder  is  saline.  In  con- 
sequence of  the  very  small  quantity  of  albumen  in  it,  neither 
acids  nor  heat  coagulate  it  to  a  striking  degree. 

The  vitreous  humour  is  supplied  with  a  branch  from  the  cen- 
tral artery  of  the  retina.  This  branch  does  not  convey  red 
blood,  but  only  serum,  except  in  the  foetal  eye.  It  may  be  in- 
jected, at  almost  any  age,  with  size,  coloured  with  vermilion; 
but  is  then,  of  course,  put  very  much  on  the  stretch.  It  has 
been  well  described  by  Zinn.  It  penetrates  the  vitreous  hu- 
mour near  the  optic  nerve,  and  is  disseminated  by  very  fine 
branches  on  the  periphery,  and  on  the  internal  cellular  struc- 
ture of  the  tunica  hyaloidea.  M.  J.  Cloquet  has  described  par- 


THE  BALL  OP  THE  EYE.  425 

ticularly  one  branch,  which,  running  through  the  centre  of  the 
vitreous  humour,  in  an  appropriate  canal,  is  spent  by  small  ra- 
mifications upon  the  posterior  part  of  the  capsule  of  the  lens. 

Some  anatomists*  speak  of  a  fluid  between  the  tunica  hyaloi- 
dea  and  the  retina:  when  it  does  exist,  it  in  all  probability  is 
the  fluid  of  the  vitreous  humour,  which  has  strained  through 
the  tunica  hyaloidea  after  death. 

The  Lens  (Lens  Crystallind]  or  the  Crystalline  Humour,  as 
it  is  very  generally  called,  is  placed  immediately  behind  the 
pupil,  in  a  depression  on  the  front  of  the  vitreous  humour.  Its 
shape  is  that  of  a  doubly  convex  lens,  of  which  the  posterior 
convexity  is  greatest,  being  the  section  of  a  sphere  whose  dia- 
meter is  from  four  to  five  lines,  while  the  anterior  convexity 
is  in  the  proportion  of  a  sphere  of  from  six  to  nine  lines.  The 
usual  breadth  of  the  lens  is  about  three  and  a  half  lines.  It, 
however,  varies  its  shape  in  a  remarkable  degree  at  the  differ- 
ent periods  of  life;  immediately  after  birth  it  is  spheroidal,  in 
about  six  years  afterwards  its  lenticular  shape  is  well  marked, 
and,  subsequently,  it  becomes  more  flat  and  thin. 

The  lens  naturally  is  perfectly  transparent.  In  the  greater 
part  of,  its  thickness  it  has  the  consistence  of  half  dissolved  glue, 
but  its  centre  is  much  more  solid;  this  change,  however,  is  ef- 
fected successively.  When  it  is  subjected  to  the  mineral  acids, 
to  heat,  to  alcohol,  and  several  other  agents,  it  becomes  much 
more  solid  throughout;  it  may  then  be  separated,  like  an  onion, 
into  a  series  of  concentric  lamellae,  subdivisible  into  longitu- 
dinal fibres.  Besides  these,  there  are  fibres  more  or  less  ob- 
lique which  hold  the  lamellae  together.  These  arrangements 
prevail  from  the  centre  to  the  circumference  of  the  lens;  and 
between  its  laminse  there  is  a  diaphanous  humour  resembling 
that  between  it  and  its  capsule.t 

The  lens  is  invested  by  a  capsule  which  is  a  complete  sac, 
having  exactly  its  shape,  but  separated  from  it,  to  a  very  in- 
considerable extent,  by  the  transparent  humour  just  alluded 
to,  called  the  Liquor  Morgagni.  The  capsule  is  covered  in 
front  by  a  layer  of  the  tunica  hyaloidea  adhering  very  closely 

•  Bichat,  Anat.  Descrip.  f  J.  F.  Meckel. 


426  NERVOUS  SYSTEM. 

to  it,  but  which,  in  one  instance,  I  was  enabled  to  peel  off  par- 
tially in  the  eye  of  a  sheep,  from  one  side  to  the  other.  The 
capsule  is  covered,  in  like  manner,  on  its  posterior  face  by  the 
tunica  hyaloidea;  but  the  two  may  be  separated  there  more  ea- 
sily, according  to  the  observations  of  Bichat.  Some  of  the 
most  distinguished  continental  anatomists  are  decidedly  in  fa- 
vour of  the  capsule  of  the  crystalline  being  a  complete  bag;  but 
it  is  rather  unsettled  whether  the  exterior  margin  of  the  capsule 
bounds  the  lesser  circumference  of  the  canal  of  Petit,  or  whether 
the  two  layers  of  the  tunica  hyaloidea  unite  previously  at  the 
circumference  of  the  capsule.  The  latter  seems  to  be  the  opi- 
nion of  M.  J.  Cloquet.  Dr.  Physick,  in  some  cases  of  mem- 
branous cataract,  has  succeeded  in  drawing  out  the  capsule  en- 
tire, so  as  to  exhibit  its  whole  extent  when  floated  in  water. 

The  capsule  in  front  of  the  lens  is  much  thicker  than  the  tu- 
nica hyaloidea,  and  its  difference  of  character  from  the  latter 
appears  to  me  to  be  very  strongly  marked.  For,  notwithstand- 
ing its  immersion  in  spirits  of  wine,  it  retains  its  transparency; 
it  is  hard  and  elastic,  and  when  clipped  with  the  scissors,  gives 
nearly  the  same  sensation  as  the  thin  paring  of  a  finger  nail 
would;  or,  as  has  been  observed  by  Haller,  it,  in  this  respect, 
resembles  the  cornea.  The  analogy  with  the  cornea  ceases, 
however,  at  this  point:  for  the  cornea  has  always  so  much  albu- 
minous matter  in  it  as  to  be  rendered  turbid  when  it  is  immersed 
in  alcohol.  The  posterior  section  of  the  capsule  of  the  lens,  is 
not  so  well  marked  either  by  its  thickness  or  specific  characters 
as  the  anterior,  yet  our  preparations  in  the  University  demon- 
strate its  existence  equally  as  conclusively.  It  is  more  assimi- 
lated to  the  nature  of  the  tunica  hyaloidea. 

In  the  injected  foetal  eye,  the  artery  of  the  tunica  hyaloidea 
which  comes  from  the  central  one  of  the  retina,  is  seen  to  fur- 
nish several  minute  ramifications  to  the  posterior  face  of  the 
lenticular  capsule;  some  of  its  branches  also  go  to  the  front  of 
the  capsule,  but  the  latter  part  is  furnished  principally  by  arte- 
rioles  from  the  ciliary  body  of  the  choroides.  The  two  sets  of 
arteries  anastomose  with  each  other;  some  of  the  latter  are  also 
spent  upon  the  membrana  pupillaris. 

The  point  is  yet  doubtful  whether  any  of  these  arteries  pene- 
trate into  the  body  itself  of  the  crystalline  humour.  Ruysch, 


THE  BALL  OF  THE  EYE.  427 

Albinus,  and  Haller,  assert  the  fact  of  their  having  seen  and  in- 
jected them  in  the  human  species  and  in  animals,  and  J.  F. 
Meckel  admits  their  testimony.  Yet  there  are  not  many  ana- 
tomists who  can  corroborate  it  by  their  personal  observations. 
It  is  sufficiently  reasonable  to  admit  it;  for  without,  we  cannot 
conveniently  account  for  the  growth  and  nutrition  of  the  lens, 
as  well  as  the  morbid  changes  which  occur  in  it.  It  should  be 
observed  that  if  this  vascular  connexion  do  exist,  it  is  a  very 
weak  one:  for  the  lens  seems  to  be  simply  surrounded  by  its 
capsule  without  adhering  to  it. 

Some  veins  which  discharge  into  the  veins  of  the  choroid 
coat,  have  been  observed  by  Walter*  on  the  posterior  part  of 
the  capsule.  It  should  be  continually  borne  in  mind  that  nei- 
ther the  arteries  nor  veins  of  the  healthy  crystalline,  nor  of  its 
capsule  convey  red  blood:  in  which  respect  they  correspond 
with  the  hyaloidea;  for  if  this  were  the  case,  vision  would  be 
very  much  disordered  by  it.  It  may  be  that  the  moats  or 
speck  seen  in  ophthalmia  arise  from  the  grosser  particles  of  the 
blood,  getting  into  these  serous  vessels  by  the  dilatation  of  the 
latter. 

The  Lens  and  its  Capsule  are  devoid  of  nerves,  at  least  none 
have  been  as  yet  traced  into  them. 

The  Aqueous  Humour  (Humor  *flquosiis}  occupies  the  space 
which  is  between  the  anterior  face  of  the  crystalline  capsule, 
and  the  posterior  face  of  the  cornea.  This  space  is  unequally 
divided  by  the  iris  into  two  chambers,  of  which  the  anterior  is 
in  front  of  the  latter  membrane,  and  the  posterior  behind  it. 
In  consequence  of  the  convexity  of  the  lens,  the  posterior  cham- 
ber has  but  very  little  depth  just  behind  the  pupil;  but  its  space 
is  augmented  at  the  circumference  of  the  crystalline,  so  as  to 
leave  room  for  the  floating  of  the  ciliary  processes  and  for  the 
motions  of  the  iris.  The  posterior  chamber  is,,  therefore,  a 
circular  vacuity ;  the  centre  of  which,  from  the  projection  of  the 
centre  of  the  crystalline,  has  scarcely  any  appreciable  depth. 
The  anterior  chamber,  in  its  shape  resembles  the  segment  of  a 
sphere:  its  depth  depends  essentially  on  the  size  and  the  projec- 
tion of  the  cornea. 

*  De  Oculis.     Berlin,  1778. 


428  NERVOUS  SYSTEM. 

The  aqueous  humour  is  perfectly  transparent,  and  almost  as 
fluid  as  water.  The  analysis  of  Berzelius  exhibits  98  parts  of 
water,  1  of  hydrochlorate  and  lactate  of  lime,  .75  of  some  ani- 
mal matter  soluble  in  water,  and  a  very  small  quantity  of  albu- 
men. From  the  latter  circumstance  it  will  be  understood  how 
this  fluid  refuses  to  coagulate  on  the  addition  of  alcohol  or  of 
mineral  acids  to  it,  and  is  only  rendered  in  a  very  slight  de- 
gree turbid  by  them.  The  rapidity  of  the  exhalation  of  this 
fluid  is  remarkable;  when  the  whole  of  it  is  lost  in  the  opera- 
tion for  cataract,  it  is  regenerated  in  from  twenty-four  to  thirty- 
six  hours.  Its  source  has  been  sought  for  in  supposititious  canals 
and  glands,  but  the  more  probable  opinion  is,  that  it  may  come 
from  any  or  all  of  the  exhalent  arteries  of  the  chambers  of  the 
eye. 

Like  the  other  two  humours  of  the  Eye,  the  aqueous  is  fur- 
nished with  a  capsule,  but  whether  it  is  complete  or  not  is  yet 
undetermined.     By  immersing  the  eye  in  hot  water,  or  in  al- 
cohol, this  capsule  may  be  readily  detected  on  the  posterior  face 
of  the  cornea,  and  to  the  greater  circumference  of  the  iris;  it 
may  even  be  traced  for  some  distance  on  the  front  surface  of 
Che  latter.     Some  of  the  French  anatomists,  as  Demours,*  De- 
scemet,  and  J.  Cloquet,  have  asserted  that  it  continued  also 
through  the  pupil  to  line  the  posterior  chamber.     An  opinion 
like  this,  from  the  extreme  tenuity  of  .the  part,  must  be  rather 
the  result  of  conjecture  than  of  accurate  observation;  it  has, 
therefore,  never  found  its  way  with  full  force  into  the  writings 
of  anatomists.     The  condition  of  the  pigmentum  nigrum  on  the 
posterior  face  of  the  iris,  and  on  the  ciliary  processes,  would 
seem  to  be  an  objection  to  the  existence  of  this  capsule  in  the 
posterior  chamber  of  the  eye.     But  if  it  really  does  exist  there, 
as  is  pretended   by  M.  Portal,  who  supposes  it  to  be  derived 
from  the  tunica  hyaloidea,  its  structure  is  incomparably  more 
delicate  than  that  part  on  the  cornea,  and,  indeed,  is  merely 
glutinous. 

The  Chambers  of  the  Eye,  till  the  seventh  month  of  foetal 
existence,  and  sometimes  later,  are  perfectly  separated  from 
each  other  by  the  Membrana  Pupillaris,  called  so  from,its  po- 

•  Demours,  Lettre,  1767. 


THE  BALL  OF  THE  EYE.  429 

sition  in  the  pupil  of  the  iris.  It  was  discovered  in  1740,  by 
Wachendorf,  and  is  sometimes  called  after  his  name.  It  is 
a  thin,  delicate,  and  transparent  membrane,  which  is  stretched 
across  the  pupil  from  its  circular  margin,  and  may,  by  its  co- 
lour, be  readily  distinguished  from  the  iris,  when  it  has  been 
made  somewhat  turbid  by  alcohol. 

The  Membrana  Pupillaris  consists,  according  to  M.  J.  Clo- 
qu*et,*  of  two  laminae  placed  back  to  back,  of  which  the  fore- 
most is  a  continuation  of  the  membrane  which  lines  the  ante- 
rior chamber  of  the  eye,  and  the  hindmost  of  that  which  lines 
the  posterior  chamber.  According  to  this,  it  may  be  noted 
that  each  chamber  has  its  distinct  capsule.  This  membrane  is 
very  vascular;  some  of  its  arteries  are  those  which  subsequently 
form  the  internal  arterial  circle  of  the  iris,  and  they  radiate  from 
the  circumference  to  the  centre  of  the  membrane;  others  come 
directly  from  the  long  ciliary  arteries,  and  others  again  from 
the  arteries  of  the  crystalline  capsule.  These  several  vessels 
are  found  principally  on  its  posterior  face.  Its  veins  have  not 
not  been  observed. 

This  membrane  first  shows  itself  about  the  third  month  of 
foetal  existence,  and  is  most  perfect  at  the  seventh;  from  the 
latter  period  it  begins  to  decline,  by  disappearing  from  the  cen- 
tre to  the  circumference.  At  the  ninth  month  it  consists  only 
in  a  few  loose  flocculent  masses  adhering  to  the  pupil.  M.  J. 
Cloquet  has  ascertained  that  its  vessels  do  not  participate  in  its 
destruction,  but  that  the  arches  which  they  form  are  retracted 
to  the  margin  of  the  pupil,  and  there  form  the  lesser  arterial 
circle  of  the  iris.  From  the  observations  of  Drs.  Jacob  and 
Tiedemann,  it  appears  that  traces  of  the  membrana  pupillarls 
exist  for  ten  or  fifteen  days  after  birth.  The  latter,  in  one  case, 
injected  its  vessels  in  a  foetus  at  full  term.t 

*  Journal  Universelle  cles  Sc.  Med.  Paris,  1818.  Mem.  sur  la  Memb.  Pupill, 
Paris,  1818. 

•j;  Am.  Med.  Jour.  vol.  i.  p_  192. 


VOL.  II.— 55. 


430  NERVOUS  SYSTEM. 


CHAPTER  III. 


OF  THE  EAR. 

THE  ear,  the  organ  of  hearing,  is  placed  principally  within 
the  petrous  portion  of  the  temporal  bone,  and  consists  in  the  Ex- 
ternal Ear,  the  Tympanum,  and  the  Labyrinth. 


SECT.  I. OF  THE  EXTERNAL  EAR. 

The  position  of  this  portion  of  the  organ  is  familiar  to  every 
one.  It  is  useful  in  collecting  the  rays  of  sound,  and  in  convey- 
ing them  to  the  more  internal  parts.  It  is  formed  by  the  struc- 
ture, exterior  to  the  petrous  bone,  called,  in  common  language, 
the  Ear;  and  by  a  bony  canal  which  leads  internally  to  the  tym- 
panum. The  basis  of  the  first  portion  is  cartilaginous,  on  which 
circumstance  it  depends  for  the  permanency  of  its  shape. 

The  ear,  of  common  language,  is  divided  into  two  parts,  Pin- 
na* and  Lobus:  the  former  is  the  most  extensive,  as  it  compre- 
hends all  the  cartilaginous  portion :  the  latter  is  attached  to  the 
inferior  margin  of  the  former,  and,  having  no  cartilage  in  its 
composition,  is  soft  and  pendulous. 

In  the  centre  of  the  external  ear  is  a  deep  depression  called 
the  Concha ;  in  the  bottom  of  it  is  the  orifice  of  the  canal  lead- 
ing to  the  tympanum,  and  called  Meatus  Auditorius  Externus. 
The  circumference  of  the  pinna  is  convoluted  into  a  scroll  called 
the  Helix,  and  commences  just  above  the  meatus  by  a  ridge. 
This  ridge  divides  the  concha  into  two  unequal  cavities,  of  which 
the  lower  is  the  larger.  The  scroll  becomes  gradually  less  pro- 
minent, till  it  terminates  at  the  posterior  inferior  part  of  the  pin- 
na, in  the  lobus. 

The  Antihelix  is  the  slightly  curved  and  vertical  eminence  in 

*  From  some  resemblance  to  a  certain  shell  fish. 


THE  EXTERNAL  EAR*  431 

the  middle  of  the  pinna;  its  lower  part  forms  the  posterior  boun- 
dary of  the  concha,  and  its  upper  part  bifurcates  into  two  small 
ridges,  between  which  there  is  a  depression  called  the  Scapha. 
Between  the  antihelix  and  the  posterior  half  of  the  helix,  is  an 
oblong  depression  called  the  Fossa  Innominata. 

The  Tragus  is  a  cartilaginous  elevation  of  the  pinna  placed  in 
front  of  the  concha,  and  inclining  somewhat  over  it ;  opposite  to 
it,  at  the  inferior  part  of  the  concha,  is  the  Antitragus. 

The  cartilaginous  plate  upon  which  the  external  ear  depends 
for  its  shape  is  of  a  thickness  very  nearly  uniform ;  of  course,  the 
ridges  and  depressions  on  its  exterior  surface  have  correspond- 
ing depressions  and  ridges  on  the  side  next  to  the  head.  It  is 
interrupted  at  several  places  by  fissures ;  for  example,  there  is 
one  of  considerable  size  filled  up  with  ligamentous  matter,  which 
separates  the  upper  margin  of  the  tragus  from  the  beginning  of 
the  helix :  there  is  another  between  the  lower  extremity  of  the 
antihelix  and  the  antitragus.  In  the  tragus,  there  are  two  and 
sometimes  three  small  narrow  ones,  said,  by  Santorini,  to  be 
filled  with  muscular  fibres;  but  the  latter  assertion  does  not  cor- 
respond with  the  observations  of  subsequent  anatomists,  as  the 
matter  appears  fibrous. 

The  external  ear  is  united  to  the  side  of  the  head  by  three 
ligaments.  The  anterior  arises  from  the  root  of  the  zygomatic 
process  above  the  articulation  of  the  lower  jaw,  and  is  inserted 
into  the  pointed  production  of  cartilage  on  the  fore  part  of  the 
helix.  The  posterior  arises  from  the  swell  of  the  temporal  bone, 
which  runs  into  the  front  margin  of  the  base  of  the  mastoid  pro- 
cess, and  is  inserted  into  the  convex  side  of  the  concha,  at  the 
beginning  of  the  meatus  auditorius.  The  superior  arises  from  the 
temporal  aponeurosis,  and  is  inserted  into  the  upper  part  of  the 
concha.  These  ligaments  lie  immediately  below  the  muscles 
destined  to  move  the  ear. 

The  Meatus  Auditorius  Externus,  is,  in  the  adult,  an  inch  in 
length,  reckoning  from  its  external  orifice  to  the  membrane  of 
the  tympanum,  which  closes  it  inwardly.  It  is  about  three  lines 
in  diameter,  is  rather  oval  than  cylindrical,  and  somewhat  smaller 
in  the  middle  than  at  either  of  its  extremities.  It  runs  inwards, 


432  NERVOUS  SYSTEM. 

with  a  slight  inclination  forwards ;  the  exterior  half  is  formed  by 
the  cartilage  of  the  pinna,  and  the  internal  half  by  the  temporal 
bone :  it  departs  from  the  horizontal  course,  in  being  curved  at 
its  middle  where  the  two  sections  join.  This  curvature  has  its 
convexity  upwards,  so  that  when  we  wish  to  look  to  the  bottom 
of  the  canal,  the  external  ear  must  be  pulled  upwards  and  back- 
wards. 

The  cartilaginous  portion  of  the  meatus  auditorius,  is  formed 
by  a  triangular  piece  springing  from  the  base  of  the  tragus  and 
from  the  inferior  anterior  part  of  the  concha.  This  portion 
is  nearly  a  tube,  but  is  interrupted  above  and  behind  by  the  in- 
tervention of  a  dense  fibrous  tissue,  continuous  with,  arid  indeed 
the  same  with  that  which  joins  the  helix  and  the  tragus.  The 
internal  margin  of  the  cartilaginous  meatus  forms  a  point  below ; 
and  adheres  by  ligament  very  closely  to  the  asperities  on  the 
margin  of  the  bony  meatus.  If  there  were  no  fissures  in  the  ex- 
ternal ear,  it  would,  therefore,  be  almost  immoveable. 

The  skin  covering  the  external  ear,  is  more  delicate  than  in 
most  other  parts  of  the  surface  of  the  body.  Its  sebaceous 
glands  or  follicles  are  very  abundant,  and  in  infants  secrete  free- 
ly their  peculiar  fluid.  When  a  slight  inflammation  occurs,  this 
discharge  is  frequently  purulent  without  erosion.  A  duplication 
of  the  skin,  containing  a  delicate  granulated  adeps  with  some 
fibrous  matter,  constitutes  the  lobe  of  the  ear. 

The  skin,  after  lining  the  concha,  descends  into  the  meatus 
auditorius,  and  lines  it  also  as  well  as  the  external  face  of  the 
membrane  of  the  tympanum.  It  adheres  moderately  to  the 
cartilaginous  part  of  the  tube,  and  more  tenaciously  to  its  fibrous 
portions:  between  it  and  the  latter,  are  found  many  small  reddish 
bodies,  generally  oval,  the  Glandulse  Ceruminosae,*  from  which 
proceeds  the  earwax. ,  The  skin  is  extremely  thin  in  the  bony 
meatus,  adheres  closely  to  its  periosteum,  and  is  highly  sensible : 
where  it  forms  the  exterior  layer  of  the  membrane  of  the  tym- 
panum, it  may  be  detached  from  the  latter  with  the  slightest 
force,  and  seems  to  be  converted  almost  entirely  into  cuticle. 

% 

*  Duvcrney,  (Euvres  Anatoroiqites. 


THE  EXTERNAL  EAR.  433 

A  slight  maceration  or  incipient  putrefaction  frequently  enables 
one  to  draw  the  cuticle  out  entire  from  the  meatus,  so  that  it 
looks  in  shape  like  the  finger  of  a  small  glove. 

The  dermoid  lining  of  the  meatus  is  studded  with  fine  hairs, 
which  serve  to  keep  out  small  bodies  that  may  be  floating  in  the 
air.  A  considerable  number  of  small  pores  are  also  seen  in  it, 
which  are  the  orifices  of  the  ducts  of  the  ceruminous  glands. 
The  discharge  of  the  latter,  when  first  secreted,  is  thin  and 
white :  by  evaporation,  it  becomes  thick  and  yellow,  and  by  ac- 
cumulating obstructs  the  passage. 

There  are  several  small  muscles  situated  on  the  external  ear, 
which  are  for  the  most  part  so  feebly  developed  that  they  cannot 
always  be  found,  and  when  they  do  exist  they  seem  more  like 
the  rudiments  of  what  is  well  marked  in  animals,  than  intended 
for  a  special  purpose  in  the  human  body. 

1.  The  Helicis  Major  is  an  oblong  fasciculus,  situated  on  the 
front  of  the  helix.     By  its  lower  end  it  is  attached  to  the  point 
of  cartilage  on  the  front  of  the  helix,  and  its  other  extremity  ex- 
tends to  the  top  of  the  latter. 

2.  The  Helicis  Minor  is  a  small  square  fasciculus,  also  on  the 
front  of  the  helix,  between  the  folded  margin  of  the  latter  and 
the  inferior  half  of  the  helieis  major. 

3.  The  Tragicus  is  a  square  fasciculus,  on  the  front  surface  of 
the  tragus,  near  its  margin :  its  upper  extremity  sometimes  runs 
into  the  helieis  major. 

4.  The   Antitragicus  is    a   small   oblong   fasciculus,  which 
arises  from  the  upper  extremity  of  the  antitragus,  and  going 
upwards  it  is  inserted  into  the  inferior  extremity  of  the  anti- 
helix. 

5.  The  Transversus  Auriculae  is  on  the  internal  surface  of  the 
pinna.     It  arises  from  the  prominence  of  the  concha,  and  is  in- 
serted into  the  hollow  dorsum  of  the  antihelix. 


434  NERVOUS  SYSTEM. 

There  are  some  other  muscles  which  may  be  uniformly  found 
and  are  intended  to  move  the  external  ear  upon  the  side  of  the 
head,  though  from  the  want  of  exercise  there  are  very  few  in- 
dividuals capable  of  making  them  contract.  They  are  as  fol- 
low:— 

1.  The  Attollens  Auriculae  is  placed  on  the  side  of  the  head 
beneath  the  integuments :  it  is  a  broad,  thin,  and  somewhat  tri- 
angular muscle,  which  arises  from  the  inferior  margin  of  the 
tendon  of  the  occipito-frontalis,  and  from  the  temporal  aponeu- 
rosis.     It  becomes  narrower  in  its  descent,  and  is  inserted  ten- 
dinous into  the  upper  end  of  the  pinna  by  the  elevation  corre- 
sponding with  the  scapha. 

Its  name  implies  its  action  to  be  that  of  raising  the  pinna. 

2.  The  Retrahens  Auriculae,  consists  in  two  or  three  oblong 
fasciculi,  placed  parallel,  and  one  above  the  other.     It  arises 
from  the  mastoid  portion  of  the  temporal  bone,  above  the  mas- 
toid  process,  and  is  inserted  tendinous  into  the  convex  side  of 
the  concha  near  the  meatus  auditorius. 

It  draws  the  pinna  backwards. 

3.  The  Anterior  Auriculae  is  a  small  quadrangular  slip,  just 
above  the  root  of  the  zygomatic  process.     It  arises  from  the 
temporal  fascia,  and  is  inserted  tendinous  into  the  fore  part  of 
the  helix  just  above  its  beginning. 

It  draws  the  pinna  forwards  and  upwards. 


SECT.  II. — OF  THE  TYMPANUM. 

The  Tympanum  is  the  middle  portion  of  the  organ  Of  hear- 
ing, being  interposed  between  the  meatus'  auditorius  and  the 
labyrinth.  Its  depth  is  about  three  lines,  its  antero-posterior  di- 
ameter about  six,  and  its  vertical  diameter  rather  more,  though 
from  the  general  inequality  of  the  cavity,  and  its  communication 
with  adjoining  cavities,  it  is  not  easy  to  fix  upon  very  precise 
measurements. 


THE  TYMPANUM.  435 

The  Membrana  Tympani,  is  a  complete  membranous  septum, 
interposed  between  the  meatus  externus  and  the  tympanum.  It 
is  placed  very  obliquely,  so  that  its  upper  edge  inclines  outwards, 
and  its  under  edge  inwards ;  the  latter,  therefore,  forms  a  very 
acute  entering  angle  with  the  inferior  part  or  floor  of  the  meatus, 
and  gives  to  that  portion  of  the  meatus  an  additional  length, 
which  renders  it  difficult  to  see  to  its  bottom.  The  membrane 
of  the  tympanum  is  nearly  circular,  and  has  its  circumference 
adhering  very  closely  to  the  external  orifice  of  the  tympanum. 
It  is  slightly  tense,  and  has  its  middle  drawn  inwards  by  being 
attached  to  the  handle  of  the  malleus. 

The  membrana  tympani  consists  of  four  laminae ;  the  two  ex- 
terior of  which,  being  the  cuticle  and  the  cutis  vera,  which  line 
the  meatus  auditorius,  are  easily  detached,  as  mentioned  before, 
and  seem  scarcely  to  adhere  to  the  layer  below.  The  third  layer 
is  the  proper  membrane,  and  is  distinguished  by  its  dryness  and 
by  its  transparency.  Sir  Everard  Home  was  enabled  to  de- 
tect radiated  muscular  fibres,  forming  it  in  the  elephant.*  In 
the  human  subject,  its  fibrous  character  is  best  seen  on  its  inter- 
nal face,  but  the  radiated  arrangement  is  not  so  distinct.  Cal- 
dani  considers  it  as  formed  by  filaments,  decussating  each  other 
at  right  angles,  and  intermixed  with  blood  vessels.t  The  inter- 
nal layer  is  a  continuation  of  the  lining  membrane  of  the  tym- 
panum; it  is  separated  with  some  difficulty,  owing  to  its  tenuity. 

The  proper  membrane  of  the  tympanum,  when  successfully 
injected,  exhibits  a  high  degree  of  vascularity  ;J  though,  in  its 
natural  state,  but  very  few  red  blood  vessels  are  seen  in  it. 

The  floor  of  the  tympanum,  or  the  side  next  to  the  labyrinth, 
presents  an  unequal  surface.  In  its  middle  is  a  well  marked 
rising,  the  Promontory,  (Promontoriumj)  formed  by  one  end  of 
the  labyrinth.  Just  above  the  superior  margin  of  this  promi- 
nence, near  its  centre,  is  an  oval  opening,  called,  from  its  shape, 
Foramen  Ovale,  or  Fenestra  Ovalis;  having  its  long  diameter 
horizontal,  its  superior  margin  rounded  or  concave,  and  its  infe- 
rior straight.  At  the  posterior  inferior  part  of  the  promontory 

*  Philosophical  Transactions,  for  1800.  London. 

f  Plate  XCVII1,.  Anat. 

$  Ruyschii,  Epist.  Anat.  Probl.  viii.     Anatomical  Museum. 


436  NERVOUS  SYSTEM. 

is  another  opening,  which,  though  somewhat  triangular,  is  called 
the  Foramen  Rotundum,  or  Fenestra  Rotunda,  and  in  the  dried 
bone  leads  to  the  cochlea,  but  is  naturally  stopped  by  the  lining 
membrane  of  the  tympanum.  According  to  M.  Ribes,  this 
membranous  plug  has  also  two  other  layers,  an  internal  one,  the 
continuation  of  what  lines  the  cochlea,  and  a  middle  one,  which 
is  peculiar.  In  these  respects,  there  is  a  correspondence  with 
the  membrana  tympani. 

The  Eminentia  Pyramidalis  is  a  small  conical  eminence  pro- 
jecting from  the  posterior  part  of  the  tympanum,  on  a  line  with 
the  fenestra  ovalis.  It  is  hollow,  contains  a  muscle,  and  com- 
municates at  the  other  end  with  the  Canal  of  Fallopius.  Lower 
down,  and  more  externally,  there  is  a  small  orifice,  (Apertura 
Chorda,}  through  which  the  nerve  called  Chorda  Tympani 


The  Mastoid  Portion  of  the  Temporal  bone,  in  the  adult, 
abounds  in  large  cells  or  sinuses,  which  communicate  freely 
with  one  another.  They  are  distinct  from  the  diploic  structure 
of  the  bone,  as  they  contain  no  meditullium,  and  are  lined  by  a 
continuation  of  the  internal  membrane  of  the  tympanum,  which 
is  extremely  thin  upon  them.  The  orifice  of  communication  be- 
tween these  cells  and  the  tympanum,  is  placed  at  the  superior 
posterior  part  of  the  latter :  it  is  rough  and  irregular,  and  par- 
tially occupied  by  the  short  leg  of  the  incus.  Just  in  front  of 
this  opening,  the  cavity  of  the  tympanum  is  extended  vertically, 
for  the  purpose  of  accommodating  the  body  of  the  malleus  and 
of  the  incus,  whereby  they  are  in  a  great  degree  concealed, 
unless  the  corresponding  margin  of  the  tympanum  be  cut  away. 

At  the  fore  part  of  the  tympanum  is  the  Eustachian  Tube, 
which  runs  for  six  or  eight  lines  in  the  substance  of  the  petrous 
bone,  near  its  exterior  margin ;  and  then  terminates  in  a  carti- 
laginous and  membranous  portion,  which  communicates  with 
the  pharynx  at  the  posterior  naris.  The  latter  extremity  of  the 
Eustachian  Tube  is  placed  on  a  line  with  the  posterior  end  of 
the  inferior  spongy  bone.  Its  orifice  is  rounded  or  oval,  is  large 
enough  to  admit  the  tip  of  the  little  finger,  and  reposes  against 


THE  TYMPANUM.  437 

the  side  of  the  internal  pterygoid  process  of  the  sphenoid  bone. 
Though  almost  within  the  precincts  of  the  posterior  naris,  this 
orifice  is  to  be  considered  as  opening  into  the  pharynx. 

This  canal,  in  its  whole  length,  measures  nearly  two  inches, 
and,  with  the  exception  of  the  portion  in  the  petrous  bone,  is 
cartilaginous  and  membranous.  The  cartilage  is  a  single,  thick, 
triangular  plate,  flat,  and  adhering  by  one  of  its  edges  to  the 
pterygoid  process.  The  under  part  of  the  tube  is  membranous, 
thin,  and  affords  attachment  to  some  of  the  muscles  of  the  soft 
palate.  Its  course  is  nearly  horizontally,  backward  and  out- 
ward. 

It  is  lined  in  its  whole  extent,  by  a  very  fine  mucous  mem- 
brane continuous  with  that  of  the  pharynx  and  of  the  tympanum. 
This  membrane  is  thickened  at  its  anterior  extremity  by  the 
mucous  glands  beneath  it,  which  assist  in  giving  the  marked 
elevation  to  its  orifice.  The  canal  diminishes  as  it  goes  back- 
ward, so  as  to  receive  with  difficulty  a  small  probe. 

Parallel  with  the  bony  part  of  this  canal,  but  above  it,  and  se- 
parated by  a  very  thin  partition  of  bone,  is  another  canal  which 
lodges  a  muscle  of  the  malleus.  On  the  outer  side  of  the  Eusta- 
chian  tube  is  the  glenoid  foramen,  by  which,  in  the  dried  bone, 
the  tympanum  communicates  with  the  glenoid  cavity ;  in  the  re- 
cent state  the  foramen  receives  the  long  process  of  the  malleus 
and  its^muscle,  and  transmits  the  chorda  tympani. 

There  are  four  bones  in  the  tympanum,  which,  being  succes- 
sively articulated  with  each  other,  form  a  chain,  one  end  of 
which  is  fastened  to  the  membrana  tympani,  and  the  other  end 
rests  upon  the  foramen  ovale.  They  are  the  Malleus ;  the  Incus; 
-the  Orbiculare ;  and  the  Stapes. 

The  Malleus  forms  the  fore  part  of  the  chain,  and  is  placed 
almost  vertically.  Its  superior  extremity  is  the  head,  which  is 
rounded,  with  the  exception  of  the  posterior  face,  where  a  small 
concavo-convex  surface  is  observable,  for  its  articulation  with 
the  incus.  Its  lower  extremity  is  long  and  tapering,  inclines  in- 
wardly, terminates  by  a  little  knob,  and  forms  an  angle  with  the 
part  above ;  this  portion  is  the  manubrium,  and  adheres  its  whole 

VOL.  II.—  56 


438  NEKVOUS  SYSTEM. 

length  to  the  membrana  tympani,  commencing  at  the  superior 
margin  of  the  latter,  and  insinuating  itself  between  the  internal 
and  the  proper  layer,  as  far  as  the  centre  of  the  membrane.  It 
is  this  adhesion  with  the  inclination  inwards  of  the  manubrium, 
that  causes  the  membrane  to  be  depressed  in  its  centre. 

Between  the  head  and  the  manubrium  is  a  short  portion  called 
the  neck.  From  the  superior  external  extremity  of  the  manu- 
forium  there  proceeds  outwardly  the  short  process,  (Processus 
Brevis;)  and  from  the  front  of  the  neck,  there  proceeds  the  long 
and  very  delicate  process,  concave  externally  and  convex  inter- 
nally, which  is  insinuated  into  the  glenoid  foramen,  and  is  the 
Processus  Longus,  or  Gracilis. 

The  Incus  is  behind  the  malleus,  and  is  also  upright.  It  con- 
sists in  a  body  and  two  branches,  which  diverge  very  conside- 
rably, and  has  a  general  resemblance  to  a  molar  tooth.  The 
loody  presents,  on  its  fore  part,  a  deep  concavity,  which  articu- 
lates with  the  convex  head  of  the  malleus.  The  branch  which 
arises  from  the  back  part  of  the  body  is  horizontal,  looks  into 
the  orifice  of  the  mastoid  cells,  and  is  much  shorter  than  the 
other.  The  inferior  branch  is  long,  upright,  tapering,  and  near- 
ly parallel  with  the  manubrium  of  the  malleus,  but  somewhat 
within  it. 

The  Orbiculare  is  a  very  small  flattened  sphere  of  bone,  which 
articulates  with  the  lower  end  of  the  long  process  of  the  incus, 
and  in  adult  life  is  most  generally  fused  into  it,  so  as  to  lose  its 
distinctive  character:  the  latter  change  sometimes  occurs  even 
in  early  infancy. 

The  Stapes  is  the  last  of  the  chain.  It  resembles  very  strong- 
ly the  common  stirrup  iron,  from  whence  its  name,  and  is  placed 
horizontally  at  right  angles  to  the  incus,  being  separated  from 
the  extremity  of  the  long  process  of  the  latter  by  the  os  orbicu- 
lare, and  being  directed  inwards  to  the  foramen  ovale.  It  is 
composed  of  a  head,  two  crura,  and  a  base. 

The  head  is  oblong  and  flattened :  it  has  a  slight  depression 
where  it  joins  the  orbiculare.  The  crura  are  slightly  curved, 
with  the  concavities  towards  each  other :  the  anterior  is  some- 


THE  TYMPANUM.  439 

what  straighter  than  the  posterior,  and  is  also  shorter.  They 
are  both  excavated,  longitudinally,  on  their  concave  surfaces, 
and  between  them  is  stretched  a  process  of  the  lining  membrane 
of  the  tympanum.  The  base  is  precisely  adapted  to  the  fenestra 
ovalis,  and  is  connected  to  it  by  the  lining  membrane  of  the 
tympanum,  but  not  so  closely  as  to  prevent  it  from  executing 
slight  vibratory  movements. 

Between  the  malleus  and  the  incus  there  is  a  moveable  arti- 
culation with  a  syriovial  membrane,  but  the  other  joints  of  the 
chain  are  simply  ligamentous.  - 

This  chain  of  bones  is  moved  by  several  muscles,  which  in- 
fluence the  degree  of  tension  of  the  membrana  tympani. 

1.  The  Laxator  Tympani  arises  from  the  posterior  end  of  the 
spinous  process  of  the  sphenoid  bone,  and  passing  behind  the 
articulation  of  the  lower  jaw  into  the   glenoid  foramen,  is  in- 
serted, tendinous,  along  the  processus  g^acilis  of  the  malleus. 

It  draws  the  malleus  forwards  and  outwards,  so  as  to  relax 
the  membrana  tympani. 

2.  The  Tensor  Tyrnpani  is  placed  in  the  canal  just  above  the 
Eustachian  tube.     It  arises  from  the  posterior  extremity  of  the 
cartilaginous  portion  of  the  latter,  and  having  got  into  the  tym- 
panum, is  changed  into  a  small  tendon,  which,  going  outwardly, 
is  inserted  into  the  neck  of  the  malleus,  just  below  its  processus 
gracilis. 

It  draws  the  malleus  inwardly;  consequently  makes  tense 
the  membrana  tympani,  and  drives  the  stapes  intp  the  fenestra 
ovalis. 

3.  The  Stapedius  arises  from  the  bottom  of  the  cavity  in  the 
pyramid,  and  terminates  in  a  small  round  tendon,  which,  going 
through  the  apex  of  the  latter,  is  inserted  into  the  head  of  the 
stapes. 

It  draws  the  stapes  backwards,  and  perhaps  fixes  it  more 
firmly  by  its  contractions. 

4.  There  is  a  fourth  muscle  mentioned  by  anatomists,  the  ex- 


440  NERVOUS  SYSTEM. 

istence  of  which  is  more  equivocal ;  it  is  called  the  Laxator 
Tympani  Minor.  It  arises  from  the  superior  margin  of  the  ori- 
fice of  the  tympanum,  and  is  inserted  into  the  processus  brevis 
of  the  malleus.  It  is  by  some  considered  only  as  a  ligament,  to 
which  opinion  I  am  inclined. 

Of  the  Lining  Membrane  of  the  Tympanum. 

This  membrane  is  a  continuation  of  the  lining  membrane  of 
the  pharynx,  being  introduced  into  the  tympanum  through  the 
Eustachian  tube.  It  covers  completely  the  surface  of  the  tym- 
panum, and  is  reflected  over  its  little  bones  so  as  to  give  them  a 
covering  also :  in  addition  to  which,  it  lines  such  of  the  mastoid 
cells  as  communicate  with  the  tympanum. 

This  membrane  is  extremely  delicate :  on  its  surface,  adja- 
cent to  the  bones,  it  is  somewhat  fibrous,  and  thereby  resembles 
periosteum ;  but  the  other  surface  has  the  characters  of  the  mu- 
cous membranes  generally,  in  the  nature  of  its  secretion,  and  in 
its  vascularity,  which  is  very  strongly  marked  in  inflammations, 
and  by  fine  injections.  Bichat  mentions,  that  in  certain  catar- 
rhal  affections  its  mucous  secretion  is  so  abundant  as  to  fill  the 
whole  cavity  of  the  tympanum,  and  that  without  ulceration. 
Sometimes,  in  such  cases,  the  membrane  of  the  tympanum  is 
ruptured,  and  the  discharge  finds  its  way  out  through  the  mea- 
tus  externus,  presenting  itself  under  a  purulent  form,  as  if  an 
abscess  had  formed  in  the  ear. 

SECT.  III. OF  THE  LABYRINTH.* 

The  Labyrinth  (Labyrinthus)  is  placed  on  the  inner  side  of 
the  tympanum,  in  the  thickness  of  the  petrous  bone.  Its  ex- 
terior parietes  are  bone,  but  internally  there  is  a  membranous 
structure,  having,  in  many  respects,  the  same  shape.  It  is  got 
at  with  great  difficulty  in  the  adult,  owing  to  the  compactness 
of  the  petrous  bone  which  envelops  it ;  but  in  the  foetus  of  the 
full  period,  where  it  is  almost  as  large  as  in  the  adult,  the  sur- 
rounding bone  is  of  a  softer  and  more  spongy  texture,  and  may 
be  pared  away  with  a  pen-knife  without  much  trouble.  In  the 

*  Antonio  Scarpa,  Disquisit.  de  Auditu  et  Olfacto. 


THE   LABYRINTH.  441 

latter  case,  the  parietes  of  the  bony  labyrinth  remain  about 
the  thickness  of  an  egg-shell,  and  have  very  much  the  same  de- 
gree of  consistency  and  strength. 

The  bony  labyrinth  consists  of  three  portions:  the  Vestibu- 
lum, the  Semicircular  Canals,  and  the  Cochlea. 

The  Vestibulum  is  the  cavity  to  which  the  foramen  ovale 
leads;  it,  with  the  cochlea,  occasions  the  protuberance  into  the 
tympanum,  known  as  the  promontory.  It  is  an  irregular  round- 
ed excavation,  the  surface  of  which  is  impressed  by  its  contents; 
thus,  at  the  superior  posterior  and  external  part,  next  to  the 
semicircular  canals,  there  is  a  superficial  Fossa,  called,  from  its 
shape,  Semi-Elliptica,  and  at  its  anterior  and  inferior  part,  nearer 
the  cochlea,  another,  called  Fossa  Hemi-spherica.  These  fossae 
are  marked  off  from  each  other  by  a  ridge  of  bone,  at  the  lower 
end  of  which  there  is  a  third  fossa  between  the  other  two,  called, 
by  Soemmering,  Cavitas  Sulciformis. 

There  are  seven  orifices  belonging  to  the  vestibulum  besides 
the  foramen  ovale;  five  at  its  posterior  part  leading  into  the  se- 
micircular canals;  one  anteriorly  leading  into  the  upper  scala  of 
the  cochlea:  and  the  last  placed  in  its  internal  paries  is  the  aque- 
duct of  the  vestibule.  In  addition  to  these  orifices,  the  parietes 
of  this  cavity  are  cribriform  in  the  fossa  semi-elliptica  and  near 
the  foramen  rotundum.* 

The  Semicircular  Canals  (Canales  Semicirculares)  are  at  the- 
posterior  extremity  of  the  vestibulum.  They  are  three  in  num- 
ber, and  are  named  from  their  relative  situation,  Superior  or  An- 
terior, Posterior  or  Inferior,  and  External.  Each  one  forms 
rather  more  than  the  half  of  a  semicircle,  and  has  its  cavity,, 
about  half  a  line  in  diameter:  their  orifices  are  somewhat  dilated 
beyond  this  measurement.  The  apparent  thickness  of  their  pa- 
rietes is  greater  in  the  adult  than  in  the  infant. 

The  Superior  Canal  runs  from  without  inwards  and  backwards* 
Its  anterior  orifice  is  above  the  fenestra  ovalis,  and  is  enlarged 
into  an  ampulla  or  elliptical  cavity.  At  its  posterior  extremity,, 

*  Ant.  Scarpa,  loc.  cit. 


442  NERVOUS  SYSTEM. 

it  joins  the  upper  extremity  of  the  inferior  canal,  so  that  a  com- 
mon trunk  is  thus  formed,  the  orifice  of  which  is  at  the  internal 
posterior  part  of  the  vestibulum.  and  is  dilated  into  the  shape  of 
a  funnel.* 

The  Posterior  or  Inferior  Canal  is  nearly  vertical;  has  its 
concavity  in  front,  and  its  convexity  behind,  and  joins,  as  just 
remarked,  with  the  superior;  its  inferior  orifice,  which  is  near 
the  foramen  rotundum,  is  also  enlarged  into  an  ampulla  or  ellip- 
tical cavity.  It  is  the  longest  of  the  three  canals,  and  has  its 
branches  nearer  together. 

The  External  Canal  is  nearly  horizontal,  and  is  placed  in  the 
space  left  by  the  divergence  of  the  other  two.  It  is  the  shortest 
and  the  largest  of  the  three.  Its  exterior  orifice  is  also  enlarged 
into  an  ampulla  or  elliptical  cavity,  and  is  just  behind  the  fora- 
men ovale,  or  below  the  ampulla  of  the  upper  canal;  the  inter- 
nal orifice  is  below  the  common  opening  of  the  other  two  ca- 
nals. 

It  is  the  union  of  the  superior  and  of  the  posterior  canals  at 
one  of  their  extremities,  which  reduces  the  number  of  openings 
into  the  vestibulum,  from  the  semicircular  canals  to  five  instead 
of  six. 

The  Cochlea  forms  the  fore  part  of  the  labyrinth,  and  resem- 
bles very  strongly  the  shell  of  the  common  snail.  Its  base  is 
the  bottom  of  the  meatus  auditorius  interims,  and  its  apex,.is  di- 
rected towards  the  cavity  of  the  tympanum,  so  that  the  axis  of 
the  cochlea  is  turned  downwards  and  outwards.  It  consists  in 
a  conoidal  tube  wound  spirally  twice  and  a  half  around  a  co- 
lumn of  bone  termed  the  Modiolus.  The  tube  then  of  course 
diminishes  in  size  from  the  base  to  the  apex  of  the  cochlea. 

This  conical  tube  is  divided  in  its  length  by  a  plate  called 
Lamina  Spiralis.  Of  the  two  compartments  thus  formed,  one 
is  above  the  other.  The  inferior  is  the  larger,  and  communi- 
cates at  its  base,  through  the  foramen  rotundum,  with  the  tym- 
panum; it  is,  therefore,  called  Scala  Tympani.  The  other  com- 
partment communicates  at  its  base  with  the  vestibulum,  and  is, 
therefore,  called  Scala  Vestibuli. 

*  Scarpa,  loc.  cit. 


THE  LABYRINTH.  443 

The  Mocliolus  is  of  a  conical  shape  and  cribriform:  one 
canal,  larger  than  the  others,  runs  from  its  base  to  its  sum- 
mit. This  canal  is  surrounded  by  many  others,  which  dimi- 
nish successively  as  they  advance  towards  the  apex,  and  ter- 
minate in  orifices  upon  the  lamina  spiralis.  This  cribriform 
arrangement  of  the  modiolus  is  the  Tractus  Spiralis  Foraminu- 
losus.  The  base  of  the  modiolus  is  towards  the  meatus  audi- 
torius  internus,  and  its  point  does  not  go  to  the  apex  of  the 
cochlea,  but  stops  short  of  it,  and  is  expanded  into  a  cavity 
called  the  infundibulum,  the  base  of  which  is  towards  the  apex 
of  the  cochlea.  That  portion  of  the  apex  of  the  cochlea  which 
covers  over  the  infundibulum,  is  the  Cupola. 

It  was  just  mentioned  that  the  lamina  spiralis  divides  the 
cochlea  into  two  tubes;  the  septum  thus  formed,  does  not,  how- 
ever, run  their  whole  length,  for  it  ceases  in  the  infundibulum 
by  a  small  crooked  process  of  bone,  called  the  Hamulus  Coch- 
lea. The  lamina,  when  examined  by  strong  glasses,  is  seen 
to  consist  of  four  distinct  structures  called  its  Zones.  1.  The 
Zona  Ossea  is  next  to  the  modiolus,  and  is  composed  of  two 
bony  laminae,  with  an  intermediate  diploic  structure,  in  which 
are  the  canals  for  transmitting  the  filaments  of  the  portio  mollis 
or  auditory  nerve.  2.  The  Zona  Coriacea,  on  the  outer  side 
of  this,  the  structure  of  which  is  cartilaginous.  3.  The  Zona 
Vesicularis,  said  to  contain  in  its  cells  a  pellucid  fluid.  4.  The 
Zona  Membranacea,  which  is  probably  only  the  lining  mem- 
brane of  the  cochlea,  and  completes  the  lamina  spiralis  on  its 
edge  next  to  the  periphery  of  the  cochlea.  Some  very  re- 
spectable anatomists  pass  over  this  minute  distinction  in  the 
structure  of  the  septum,  and  merely  divide  it  into  Zona  Ossea, 
and  into  Zona  Mollis. 

Of  the  Membranous  Labyrinth. 

The  whole  internal  face  of  the  bony  Labyrinth  is  lined  by 
a  very  delicate  and  vascular  membrane,  which  is  more,  distinct 
during  the  early  periods  of  intra  uterine  life.  Besides  this, 
there  is  a  membranous  labyrinth,  consisting  in  three  semicir- 
cular canals,  nearly  filling  up  the  cavities,  and  having  the  same 
-  shape  and  general  arrangement  of  the  bony  canals;  and  in  two 
sacs  contained  in  the  vestibule. 


444  NERVOUS  SYSTEM. 

The  Semicircular  Membranous  Canals  have  also  at  their 
ends  the  elliptical  enlargements  called  ampulla?;  they  termi- 
nate by  both  extremities  in  the  sac  of  the  superior  part  of  the 
vestibule.  This  sac  is  generally  called,  from  its  shape,  Sac- 
culus  Ellipticus;  and  by  Scarpa,  from  its  function,  the  Alveus 
Communis.  In  front  of  the  Sacculus  Ellipticus,  nearer  the 
cochlea,  and  opposite  the  foramen  ovale,  is  the  Sacculus  Sphe- 
ricus;  it  is  a  complete  bag,  having  no  communication  with  the 
other,  or  with  the  membranous  canals.  Both  of  the  sacs  adhere 
to  the  vestibulum  at  their  posterior  parietes. 

The  sacs  of  the  vestibule  and  the  membranous  semicircular 
canals  are  filled  with  a  very  fluid  transparent  liquid.  Accord- 
ing to  the  observations  of  M.  Ribes,  it  is  not  necessary  to  the 
function  of  hearing  that  this  fluid  should  be  so  abundant  as  to 
distend  the  membranous  labyrinth,  inasmuch  as  in  his  dissec- 
tions he  met  with  individuals  in  whom  the  latter  was  only  half 
filled,  and  yet  they  had  heard  very  well.  He  also  met  with 
similar  cases  in  which  the  fluid  was  abundant  in  the  vestibulum, 
but  deficient  in  the  canals,  and  the  reverse.  Corresponding 
observations  have  been  made  by  M.  Brugnone,  of  Turin,*  where 
lie  had  adopted  the  precaution  of  previously  freezing  the  bone, 
so  that  none  of  the  fluid  could  be  said  to  have  been  lost  by  ac- 
cident. From  the  frequency  with  which  this  deficiency  was 
observed,  his  opinion  seems  to  be  well  founded,  that  it  is  the 
most  natural  state  of  the  labyrinth. 

The  parietes  of  the  membranous  labyrinth  are  very  thin  and 
transparent;  there  is  a  very  loose  cellular  tissue  between  them 
and  the  bone,  and  they  are  susceptible  of  being  highly  coloured 
'by  injection. 

A  fluid  of  the  same  character  with  the  preceding  also  fills  the 
scalse  of  the  cochlea,  and  extends  itself  into  the  bony  vestibu- 
lum and  the  bony  semicircular  canals  upon  the  outer  surface  of 
the  membranous  labyrinth. 

•  Mem.  de  Turin,  1805—1808. 


LABYRINTH.  445 


Of  the  Aqueducts  of  the  Ear. 

The  Aqueducts  (rfqusednctus]  of  Cotunnius,  as  they  are 
tailed,  are  two  small  canals  which  go  through  the  petrous  bone 
from  the  labyrinth.  There  is  one  for  the  vestibule,  and  ano- 
ther for  the  cochlea. 

The  Aqueduct  of  the  Vestibulum,  commences  in  the  latter 
cavity,  somewhat  in  advance  of  the  common  orifice  of  the  two 
semicircular  canals;  it  goes  inwards  and  opens  on  the  posterior 
face  of  the  petrous  bone,  behind  the  meatus  internus.  It  en- 
larges gradually  in  its  course,  which  causes  it  to  have  somewhat 
of  a  triangular  shape,  and  it  is  lined  by  a  continuation  of  the 
dura  mater.  It  is  about  four  lines  long. 

The  Aqueduct  of  the  Cochlea  commences  in  the  Scala  Tym- 
pani,  near  the  foramen  rotundum,  and,  enlarging  in  its  course, 
terminates  on  the  under  surface  of  the  petrous  bone,  in  the  in- 
ternal margin  of  the  jugular  fossa,  at  the  root  of  the  little 
spine  which  separates  the  eighth  pair  of  nerves  from  the  jugu- 
lar vein. 

The  anatomist*  from  whom  these  canals  were  named,  and 
who  first  described  them,  was  under  an  impression  that  the  fluid 
of  the  labyrinth  always  filled  it  completely;  and  that  without  a 
sort  of  waste  gate  for  it  on  an  occasion,  the  vibration  of  the 
stapes  would  be  prevented  from  putting  it  in  motion,  conse- 
quently, hearing  must  cease.  These  canals,  the  existence  of 
which  is  sufficiently  obvious  in  many  subjects,  were,  therefore, 
considered  by  him  as  the  desired  avenues  for  the  discharge  of 
the  superabundant  fluid,  and  his  theory  and  descriptions  were 
very  generally  adopted.  Of  late  years,  the  investigation  of  this 
subject  has  been  renewed  by  MM.  Ribes  and  Brugnone,  and 
their  observations  are  considered  by  the  French  anatomists,  to 
have  proved  conclusively,  the  error  into  which  Cotunnius  and 
others  have  fallen. 

In  regard  to  the  aqueduct  of  the  vestibule,  M.  Ribes  has  found 
it  only  in  three  instances  emptying  into  the  vestibule;  for  most 

*  Dominici  Cotunnii,  Anat.  Dissert,  de  Aquzeduct.     Naples,  176L 
VOL.  II.— 57 


446  NERVOUS  SYSTEM. 

commonly  it  leads,  after  a  course  somewhat  tortuous,  into  the 
spongy  structure  of  the  petrous  bone,  at  the  posterior  part  of 
the  vestibule,  and  smaller  canals  diverge  from  it  in  different  di- 
rections. In  the  cases  where  it  was  connected  with  the  laby- 
rinth, it  was  so  by  several  orifices  leading  into  the  vestibule, 
and  into  the  posterior  semicircular  canal.  He  has  not  found 
this  canal  in  the  foetus  nor  till  some  time  after  birth,  and  from 
his  injections  he  believes  that,  in  all  cases,  it  and  its  branches 
are  only  intended  to  convey  blood  vessels  throughout  the  pe- 
trous bone  and  to  the  labyrinth. 

In  regard  to  the  supposed  aqueduct  of  the  cochlea,  M.  Ribes  has 
also  found  it  diverging  into  collateral  branches,  and  occupied 
by  blood  vessels,  which  are  distributed  to  the  spongy  structure 
of  the  petrous  bone,  and  to  the  tympanum. 

In  my  own  researches  on  this  point,  on  the  dried  bones,  the 
canals,  as  described  by  Cotunnius,  were  closed  at  the  labyrinth, 
in  the  case  of  subjects  advanced  in  life;  but,  in  the  middle  aged, 
and  in  infantile  specimens,  I  have  been  more  successful  in 
tracing  them  fairly  into  the  labyrinth,  and  have  the  prepara- 
tions in  the  Wistar  Museum.  At  the  same  time,  I  think  it 
much  more  probable  that  they  only  contained  blood  vessels, 
and  that  Cotunnius  was  in  error.  Besides  these  vascular  ca- 
nals, M.  Ribes  has  described  some  others  having  the  same 
use. 


SECT.  IV.— OF  THE  NERVES  OP  THE   ORGANS  OF  HEARING. 

The  Nerves  which  pass  through  the  petrous  bone,  and  are 
either  wholly  or  partially  spent  upon  the  organ  of  hearing,  come 
from  three  sources.  1.  The  Auditory  Nerve;  2.  The  Portio 
Dura;  3.  The  Trigeminus,  or  Fifth  Pair. 

The  Meatus  Auditorius  Internus  conducts  the  two  first,  and 
has  its  bottom  divided  by  a  ridge  into  two  fossae,  of  which  the 
upper  one  is  the  smaller.  This  bottom,  it  has  been  observed,  cor- 
responds with  the  base  of  the  modiolus,  and  is  cribriform.  One 
foramen,  larger  than  any  of  the  others,  and  in  the  superior  fossa, 
transmits  the  portio  dura  or  facial  nerve:  all  the  others  are  oc- 
cupied by  the  filaments  of  the  auditory  nerve. 


NERVES  OF  THE  ORGANS  OF  HEARING.          447 

1.  The  Auditory  Nerve  divides  at  the  bottom  of  the  meatus 
into  fasciculi  of  filaments;  one  of  which  penetrates  into  the  ves- 
tibulum  through  the  foramina  behind  that  for  the  portio  dura, 
and  is  distributed  upon  the  sacculus  ellipticus,  and  upon  the  am- 
pulla of  the  superior  and  of  the  exterior  membranous  canal; 
other  filaments  get  to  the  sacculus  sphericus;  and  a  third  fasci- 
culus of  filaments  is  distributed  to  the  ampulla  of  the  posterior 
membranous  canal.    These  several  filaments  are  said  to  preserve, 
when  they  first  penetrate  into  the  bony  labyrinth,  a  fibrous  ap- 
pearance, and  are  interlaced;  they  also  penetrate  the  parietes  of 
the  membranous  labyrinth,  and  have  their  extremities  bathed  in 
its  fluid,  in  which  place  they  are  converted  into  soft  pulp,  resem- 
bling mucus,  or  the  retina. 

Another  very  considerable  fasciculus  of  filaments  penetrates 
into  the  canals  of  the  modiolus,  and  enters  through  them  into 
the  cavity  of  the  cochlea,  along  the  Zona  Ossea,  and  between 
its  tables;  they  terminate  also  by  a  soft  pulp  on  the  internal  face 
of  the  lining  membrane  of  the  cochlea.  One  of  these  filaments, 
conspicuous  for  its  size,  goes  through  the  central  canal  of  the 
modiolus  and  terminates  in  the  infundibulum.* 

2.  The  Facial  Nerve,  or  Portio  Dura,  is  only  connected  to 
the  organ  of  hearing  by  sending  a  few  filaments  to  the  muscles 
of  the  bones  of  the  tympanum.     The  canal  of  the  petrous  bone, 
through  which  it  passes,  is  very  crooked;    beginning   at  the 
larger  orifice  of  the  meatus  interims  in  its  upper  fossa,  it  passes 
outwards  until  it  nearly  reaches  the  Vidian  foramen,  on  the  front 
of  the  petrous  bone;  it  then  turns  very  abruptly  backwards,  form- 
ing an  angle,  and  is  continued  in  a  circuit  around  the  superior  and 
the  posterior  parietes  of  the  tympanum,  till  it  terminates  in  the 
stylo-mastoid  foramen.     Its  course  is  marked  by  a  ridge  pro- 
jecting into  the  tympanum,  above  the  foramen  ovale,  and  pass- 
ing between  the  semicircular  canals  and  the  cochlea.     This  canal 
has  been  very  much  misnamed  by  the  calling  of  it  the  aqueduct 
of  Fallopius,  as  its  only  use  is  to  conduct  nerves  and  blood  vessels. 
It  is  lined  by  a  delicate  fibrous  membrane,  between  which,  and 

*  For  a  knowledge  of  the  minute  distribution  of  the  auditory  nerve,  the  pro- 
fession is  signally  indebted  to  the  distinguished  Scarpa,  in  his  Disquisitiones  de 
Auditu  et  Olfactu. 


443  NERVOUS  SYSTEM, 

its  contained  parts,  there  is  so  little  adhesion,  that  the  latter  may 
be  drawn  out  entire. 

The  facial  nerve  is  joined  at  the  Vidian  foramen  by  the  Vi- 
dian. nerve,  shortly  after  which  it  sends  a  filament  to  the  tensor 
tympani  muscle.*  As  it  passes  the  base  of  the  pyramid  it  de- 
taches another  filament,  which  supplies  the  stapedius  muscle.- 

Shortly  after  this,  it  is  abandoned  by  the  Vidian  nerve,  and 
does  not  give  off  any  more  branches  till  it  escapes  from  the  sty- 
lo-mastoid  foramen,  when  it  sends  off  a  branch,  the  posterior 
auricular  (Auricularis  Posterior,}  which  is  distributed  by  filaments, 
some  of  which  run  into  the  mastoid  process;  other  branches 
mount  on  the  side  of  this  process,  to  the  skin  which  covers  it, 
and  to  the  occipital  muscle:  others  go  to  the  concha  of  the  ear, 
being  spent  upon  its  skin,  upon  the  posterior  auricular  muscle, 
and  some  of  them,  penetrating  the  pinna,  are  lost  upon  the  in- 
teguments of  the  meatus  externus.  The  trunk  of  the  fascial  then 
goes  to  its  destination  on  the  face. 

4.  The  Chorda  Tympani  or  Superficial  Petrous  Nerve,  is 
a  branch  of  the  Pterygoid  branch  of  the  Trigeminus,  and  leaves 
it  near  the  anterior  part  of  the  carotid  canal  of  the  petrous  bone. 
It,  as  just  mentioned,  under  the  name  of  Vidian  nerve,  joins  the 
facial  nerve  at  the  angle  of  the  canal  of  Fallopius,  and  continues 
to  adhere  closely  to  it,  almost  to  the  styloid  foramen;  it  then 
abandons  the  facial  nerve  at  a  very  acute  angle,  and  running 
upwards  and  forwards,  gets  into  the  cavity  of  the  tympanum, 
on  a  level  with,  but  a  line  or  two  exterior  to  the  pyramid.  It 
then  crosses  the  tympanum  nearly  horizontally,  between  the 
long  crus  of  the  incus  and  the  handle  of  the  malleus,  adhering 
to  the  latter  so  as  to  be  affected  by  its  vibrations.  At  the  fore 
part  of  the  tympanum,  it  anastomoses  with  some  other  filaments 
of  the  fifth  pair,  by  which  its  size  is  augmented,  but  it  gives  no 
branches  to  the  parts  contained  in  the  tympanum.  It  then  is- 
sues from  the  latter  cavity  through  the  glenoid  foramen,  and 
descending  a  short  but  somewhat  variable  distance  along  the 
ramus  of  the  lower  jaw,  terminates  by  anastomosing  at  an  acute 
angle  with  the  lingual  branch  of  the  trigeminus. 

*  The  tensor  tympani  is  also  supplied  by  a  nerve  from  the  Third  Branch  of  the 
Trigeminus. 


NERVES  OF  THE  ORGAN  OF  HEARING.  449 

To  Mr.  John  Hunter  is  due  the  merit  of  having  traced  the 
continuity  and  identity  of  the  Vidian  nerve  with  the  chorda 
tympani.  The  continental  European  anatomists,  for  the  most 
part,  seem  ignorant  of  his  observations,  and  give  a  very  differ- 
ent account  of  the  matter.  Some  consider  it  to  arise  from  the 
facial  at  its  angle,  and  to  anastomose  at  the  other  end  with  the 
pterygoid,  or  the  reverse;  and  they  very  generally  agree  in  re- 
garding the  chorda  tympani  as  a  filament  from  the  facial,  just 
before  the  latter  gets  out  of  the  stylo-mastoid  foramen. 

The  Vidian  Nerve,  or  Superficial  Petrous,  also  traverses  the 
tympanum  in  another  place.  Just  below  the  posterior  extre- 
mity of  the  Eustachian  Canal,  there  is  a  small  foramen,  which 
leads  upwards  to  the  superior  surface  of  the  petrous  bone,  and 
downwards  to  a  small  gutter  upon  the  promontory:  this  gutter 
is  converted  into  a  canal  that  opens  upon  the  under  surface  of 
the  petrous  bone,  between  the  carotid  canal  and  the  jugular 
fossa.  Through  the  course  indicated,  passes  a  filament  from 
the  superficial  petrous  nerve:  this  filament  is  joined  by  another 
detached  from  the  sympathetic  while  in  the  carotid  canal,  and 
the  two  communicate  at  the  base  of  the  cranium  with  the  gang- 
lion of  the  glosso-pharyngeal  nerve.*  These  filaments  were 
discovered  by  Professor  Jacobson  of  Copenhagen. 

*  Meckel,  Man.  D'Anat.  vol.  iii.  p.  174.  Jacobson,  Supplemata  Act.Hafiu 
vol.  v.  p.  292.  An.  1818. 


BOOK  IX. 


PART  IV. 

Special  Anatomy  of  the  Nerves. 

CHAPTER  I. 

OF  THE  NERVES  OF  THE  ENCEPHALON. 

SECT.  I. 

THE  course  and  distribution  of  the  first  pair,  or  the  olfactory 
nerves,  have  been  described  fully  in  the  account  of  the  brain 
and  nose. 

SECT.  II. NERVUS  OPTICUS. 

The  Optic  Nerve,  as  mentioned  in  the  account  of  the  basis 
•of  the  brain,  gets  into  the  orbit  by  the  optic  foramen,  and  is 
there  entirely  surrounded  by  the  origins  of  the  muscles  of  the 
eyeball.  It  then  describes  a  slight  curvature,  of  which  the  con- 
vexity is  outwards,  and  runs  forwards  for  an  inch,  when  it  pe- 
netrates into  the  ball  of  the  eye,  where  it  gives  origin  to  or  ex- 
pands into  the  retina.  Between  the  muscles  and  it,  except  at 
their  origins,  there  is  a  mass  of  adipose  matter. 


452  NERVOUS  SYSTEM. 


SECT.  III. —  NERVTJS  MOTOR  OCULI. 

The  Nervus  Motor  Oculi,  or  third  pair,  having  reached  from 
the  basis  of  the  brain  to  the  external  side  of  the  cavernous  si- 
nus, is  placed  there  within  and  above  the  optic  nerve  and  the 
sixth  pair;  it  then  changes  its  direction,  and  penetrates  through 
the  sphenoidal  fissure  into  the  orbit,  on  the  outer  side  of  these 
nerves,  and  below  them. 

The  motor  oculi  divides,  in  the  sphenoidal  fissure,  into  two 
branches,  one  above  the  other.  The  first  crosses  over  the  op- 
tic nerve  and  the  nasal  branch  of  the  ophthalmic,  having  some 
anastomoses  with  the  latter,  and  then  distributes  its  filaments 
upon  the  rectus  superior  muscle:  some  of  them  also  penetrate 
the  latter  to  get  to  the  levator  palpebrae.  The  second  branch  is 
much  larger  than  the  first.  It  passes  between  the  optic  nerve 
and  the  rectus  inferior  muscle,  and  is  subdivided  into  three 
fasciculi:  one  for  the  rectus  internus  muscle;  another  for  the 
rectus  inferior;  and  a  third,  which  is  the  longest  and  the  small- 
est, for  the  obliquus  inferior  muscle.  The  latter  fasciculus,  not 
far  from  its  root,  gives  off  a  filament,  which,  going  along  the 
external  margin  of  the  optic  nerve,  runs  into  the  posterior  mar- 
gin of  the  lenticular  or  ophthalmic  ganglion,  and  is  its  short 
root. 

The  Lenticular  Ganglion  is  situated  on  the  outer  side  of  the 
optic  nerve,  in  the  orbit  of  the  eye,  and  is  about  a  line  in  dia- 
meter, being  flattened.  Two  nerves  concur  to  form  it:  the 
branch  just  alluded  to,  from  the  motor  oculi,  and  one  from  the 
ophthalmic  branch. of  the  trigeminus.  From  this  ganglion  arise 
the  most  of  the  ciliary  nerves;  which,  as  stated,  are  about  twen- 
ty in  number,  and  go  to.  the  choroid  coat  of  the  eye  and  to  the 
iris. 

SECT.  IV. NERVUS  TROCHLEARIS. 

The  Nervus  Trochlearis,  or  fourth  pair,  having  got  into  its 
canal  in  the  cavernous  sinus,  as  it  goes  along  the  internal  mar- 
gin of  the  ophthalmic  nerve,  receives  there  a  small  filament  from 


NERVUS  TRIGEMINUS.  453 

it*  It  then  rises  a  little,  and  enters  the  orbit  at  the  internal 
extremity  of  the  sphenoidal  fissure;  and,  going  forwards,  next 
to  the  periosteum  of  the  upper  part  of  the  orbit,  it  enters  into 
the  superior  oblique  muscle  of  the  eye,  near  its  middle,  and  is 
distributed  upon  it.  This  nerve  augments  in  volume  as  it  ad- 
vances towards  its  destination. 


SECT.  V. OF  THE  NERVUS  MOTOR  EXTERNUS. 

The  Nervus  Motor  Externus,  or  sixth  pair,  having  got  into 
the  cavernous  sinus,  is  placed  there  at  the  external  side  of  the 
internal  carotid  artery,  and  adheres  closely  to  it.  It  there  sends 
off  one  or  more  filaments,  which  follow  the  internal  carotid 
artery  through  its  canal,  and  anastomose  in  their  descent  with 
a  branch  of  the  pterygoid  nerve:  the  junction  of  these  two  forms 
the  upper  end  of  the  great  sympathetic  nerve,  and  runs  down 
to  the  superior  cervical  ganglion  of  the  sympathetic  in  two  or 
more  filaments  generally.  The  sixth  nerve  enters  the  orbit 
through  the  sphenoid  fissure,  and  is  there  closely  connected 
with  the  nervus  motor  oculi  and  the  nasal  nerve.  It  penetrates 
into  the  substance  of  the  rectus  externus  muscle,  and  is  entirely 
distributed  upon  it;  with  the  exception  that  sometimes  it  sends 
a  filament  to  the  ophthalmic  ganglion. 


SECT.  VI. OF  THE  NERVUS  TRIGEMINUS. 

This  nerve,  having  formed  the  ganglion  of  Gasser,  (Plexus 
Gangliformis,)  on  the  side  of  the  petrous  bone,  then  divides, 
as  mentioned,  into  three  large  trunks,  the  foremost  of  which  is 
the  Ophthalmic  Nerve:  the  second  fasciculus  is  the  Superior 
Maxillary;  and  the  third  the  Inferior  Maxillary  Nerve. 

The  Ophthalmic  Nerve,  or  the  first  branch  of  the  trigeminus, 
is  smaller  than  either  of  the  other  two  branches,  and  comes 
from  the  superior  part  of  the  plexus  gangliformis.  It  passes 
along  the  external  border  of  the  cavernous  sinus,  and  penetrates 

*  Simmering,  Icones  Oculi  Humani. 
VOL.  II.— -58 


454  NERVOUS  SYSTEM. 

the  orbit  through  the  sphenoidal  fissure,  on  the  outer  side  of, 
and  near  the  motor  oculi. 

In  its  whole  course  it  is  united  to  the  trochlearis  nerve  by 
close  cellular  membrane,  and  does  not  give  off  any  ramifications 
before  it  reaches  the  orbit,  with  the  exception  of  the  filament 
sent  to  the  trochlearis  nerve.  While  engaged  in  the  sphenoi- 
dal fissure  it  divides  into  three  branches;  the  nasal,  the  lachry- 
mal, and  the  frontal. 

The  Nasal  branch  of  the  ophthalmic,  is  between  the  other  two 
in  size.  It  ascends  obliquely  above  the  optic  nerve  to  gain  the 
internal  face  of  the  orbit  of  the  eye,  and  then  passes  forwards 
just  below  the  superior  oblique  muscle,  involved  in  a  quantity 
of  adipose  matter.  Shortly  after  its  origin  the  nasal  nerve  de- 
taches a  branch  (the  ramus  ciliaris)  which,  situated  at  the  ex- 
ternal margin  of  the  optic  nerve,  runs  into  the  ophthalmic  or 
lenticular  ganglion,  and  constitutes  the  long  root;  it  then  sends 
off  one  or  more  filaments,  which,  without  communicating  with 
this  ganglion,  penetrate  into  the  eyeball,  and  are  amongst  the 
ciliary  nerves  which  have  been  described. 

The  nasal  nerve,  continuing  to  pass  forward  along  the  inter- 
nal paries  of  the  orbit,  when  it  reaches  the  anterior  internal  or- 
bitary  foramen,  detaches  through  it  the  internal  nasal  or  eth- 
moidal  branch,  which,  thus  getting  into  the  cavity  of  the  cra- 
nium, goes  along  side  of  the  crista  galli,  and  then  passes  into 
the  nose  through  the  foremost  hole  of  the  cribriform  plate.  It 
then  descends  along  the  anterior  part  of  the  nose,  on  the  outer 
side  of  the  Schneiderian  membrane,  and  is  spent  by  ramifi- 
cations upon  the  contiguous  portions  of  the  latter.  Some  of 
its  terminating  branches  reach  the  tip  of  the  nose  and  the 
alae.* 

The  nasal  nerve,  after  this  branch  is  sent  off,  is  frequent- 
ly called  external  nasal,  or  nervus  infra-trochlearis.  It  con- 
tinues to  advance  along  the  under  margin  of  the  trochlearis 
muscle  and  gets  to  the  trochlea,  near  which  it  divides  into 
an  upper  and  an  under  ramuscle;  from  them  filaments  pro- 
teed  to  the  upper  and  under  eyelids,  to  the  lachrymal  sac, 

•See  Nerves  of  Nose. 


NERVUS  TRIGEMINUS. 


455 


the  caruncle,  the  tunica  conjunctiva,  and  the  muscles  on  the 
root  of  the  nose.  These  filaments  anastomose  with  the  ter- 
minating branches  of  the  frontal  nerve,  the  facial,  and  the  in- 
fra-orbitary.  According  to  Dr.  G.  Trasmondi,*  of  Rome,  two 
filaments  may  be  traced  very  distinctly  from  the  external  na- 
sal nerve  to  the  tensor  tarsi  muscle  of  the  lachrymal  sac.  They 
adhere  to  the  muscle  b^  means  of  cellular  structure,  and  pass 
on  to  its  bifurcated  extremities  and  to  the  puncta  lachryma- 
lia. 

The  Frontal  Nerve  is  the  largest  of  the  three  branches  of 
the  ophthalmic.  It  proceeds  forward  between  the  levator  pal- 
pebrae  superioris  and  the  contiguous  part  of  the  orbit,  and  in 
this  course  is  divided  into  two  branches,  the  internal  and  the 
external  frontal  nerve.  The  former  approaches  the  trochlea 
of  the  upper  oblique  muscle,  and  detaches  a  filament  to  join 
with  one  from  the  nasal  nerve.  Other  filaments  are  detached 
to  the  upper  eyelid,  some  of  which  anastomose  with  filaments 
from  the  lachrymal  nerve.  The  internal  branch  of  the  frontal 
then  issues  from  the  orbit  just  by  the  trochlea,  and,  in  ascend- 
ing, is  lost  upon  the  occipito-frontalis,  the  corrugator  super- 
cilii,  and  the  orbicularis.  The  external  branch  of  the  frontal 
issues  from  the  orbit,  through  the  supra-orbitary  foramen.  It 
quickly  detaches  a  filament,  which  goes  outwardly  to  anasto- 
mose with  the  facial;  the  remaining  part  of  the  nerve  is  distri- 
buted to  the  occipito-frontalis,  to  the  corrugator  supercilii,  to 
the  integuments  of  the  forehead,  and  to  the  scalp.  This  dis- 
tribution, according  to  Bichat,  is  best  followed  by  detaching 
the  skin,  muscles,  and  periosteum  from  the  cranium,  from  be- 
hind forwards  as  far  as  the  orbit. 

The  Lachrymal  Branch  of  the  ophthalmic  nerve  goes  for- 
wards along  the  external  side  of  the  orbit  near  the  superior 
margin  of  the  rectus  externus  muscle.  In  this  course  it  sends 
off  a  filament  through  the  spheno-maxillary  fissure  which  unites 
with  one  from  the  second  branch  of  the  fifth  pairj  it  afterwards 

*  Intorno  la  scoperta  di  due  nervi  del  Occhio  umano  ragguaglio  del  Dr.  Giu- 
seppe Trasmondi,  Professore  di  Anatomia  Practica  nel  ven.  ospidale  della  Con- 
solazione.  Roma,  1823.' 


456  NERVOUS  SYSTEM. 

sends  off  another  filament,  which,  passing  through  a  foramen 
in  the  malar  bone,  anastomoses  with  a  filament  of  the  facial 
nerve.  What  remains  of  the  lachrymal  nerve  is  then  distri- 
buted by  several  filaments  upon  the  lachrymal  gland,  the  upper 
eyelid,  and  some  of  them  reach  the  conjunctiva. 


Second  Branch  of  the  Trigeminus. 

The  Second  Branch  of  the  Fifth  Pair,  (Nervus  Maxillaris 
Superior,}  arising  from  the  middle  of  the  plexus  gangliformis, 
or  ganglion  of  Gasser,  and  also,  in  part,  from  the  common 
trunk  formed  from  the  anterior  and  posterior  roots  of  the  tri- 
geminus,  gets  from  the  cranium  through  the  foramen  rotundum 
of  the  sphenoid  bone.  While  still  in  the  cranium,  it  sometimes 
forms  an  anastomosis,  described  by  Laumonier  with  the  begin- 
ning of  the  sympathetic  nerve,  but  generally  it  does  not  detach 
any  filament  till  it  reaches  the  ptery go-maxillary  fossa. 

At  a  short  distance  after  jts  exit  from  the  cranium,  it  gives 
off  a  small  filament,  the  Nervus  Subcutaneous  Malae,  which 
ascends  into  the  orbit  through  the  spheno-maxillary  fissure, 
and  then  divides.  One  of  the  branches,  the  malar,  anasto- 
moses with  the  lachrymal  nerve,  and  leaves  filaments  with 
the  lachrymal  gland;  it  then  gets,  by  one  or  more  filaments, 
through  the  holes  of  the  malar  bone  to  the  face,  and  termi- 
nates on  the  orbicularis  muscle  and  the  skin  of  the  cheek,  anas- 
tomosing with  the  extremities  of  the  facial  nerve.  The  other 
branch,  the  temporal,  gets  into  the  temporal  fossa  by  pene- 
trating the  internal  part  of  the  malar  bone,  and,  having  anas- 
tomosed with  a  branch  of  the  inferior  maxillary  nerve,  it  goes 
outwards  and  backwards,  becomes  superficial  by  penetrating 
the  temporal  aponeurosis,  and  terminates  on  the  integuments 
of  the  temple,  anastomosing  there  with  the  branches  of  the 
facial  nerve. 

The  superior  maxillary  then  divides  into  two  trunks  much 
larger  than  the  preceding,  and  of  a  volume  nearly  equal;  the 
Infra-Orbital  and  the  Pterygo-Palatine. 

The  Infra-Orbital  (Nervus  Infra-Orbitalis)  passes  forwards, 
with  a  slight  ascent,  to  the  posterior  part  of  the  orbit,  and  en- 


NERVOUS  TRIGEMINUS.  457 

ters  the  infra-orbitar  canal.  As  it  is  about  engaging  in  the  lat- 
ter, it  detaches  a  considerable  branch,  the  Posterior  Dental. 
This  branch  descends  a  little  distance,  externally,  along  the  poste- 
rior paries  of  the  maxillary  sinus,  then  penetrates  into  the  cavi- 
ty of  the  latter.  It  terminates  by  filaments,  some  of  which  supply 
the  lining  membrane  of  the  antrum;  others  pass  through  the  little 
canals  leading  to  the  three  large  grinders,  and  enter  the  roots  of 
the  latter;  others  go  to  the  corresponding  gums.  One  branch 
goes  along  the  outer  side  of  the  sinus  to  anastomose  with  the 
anterior  dental  nerve.  The  posterior  dental,  before  it  enters 
the  bone,  also  detaches  a  branch  of  some  size,  which  winds  around 
the  tuberosity  of  the  maxillary  bone,  and  is  spent  upon  the  buc- 
cinator muscle  and  upon  the  gums. 

The  infra-orbitary  nerve  afterwards,  in  its  course  through  the 
canal,  sends  off  the  anterior  dental  nerves  from  one  or  more 
roots.  Some  of  them  detach  fibres  to  the  mucous  membrane 
of  the  nose,  where  it  covers  the  anterior  part  of  the  inferior 
turbinated  bone.  With  this  exception,  they  are  distributed, 
through  their  appropriate  canals  in  the  bone,  to  the  incisor  and 
canine  teeth,  and  to  the  corresponding  gums.  The  small  mo- 
lar teeth  are  most  frequently  supplied  by  a  union  of  filaments, 
from  the  anterior  and  posterior  dental  nerves. 

The  infra-orbitar  nerve,  on  issuing  from  the  infra-orbitar  fo- 
ramen, is  most  frequently  found  already  divided  into  several 
fasciculi,  which  may  be  classed  into  superior  and  into  inferior. 
The  former,  called  Palpebral,  radiate,  externally  and  internal- 
ly, into  filaments  which  supply  the  lower  eyelid.  One  of  these 
filaments  may  be  traced  to  the  end  of  the  nose,  where  it  anasto- 
moses with  the  internal  nasal  branch  of  the  ophthalmic;  another, 
which  terminates  about  the  internal  angle  of  the  eye,  anasto- 
moses there  with  the  external  nasal  nerve.  Others  of  its  termi- 
nating filaments,  anastomose  with  the  extremities  of  the  facial 
nerve  on  the  eyelid.  The  inferior  fasciculi  are  more  numerous 
and  large  than  the  superior.  They  descend  upon  the  face  co- 
vered by  the  levator  muscles  of  the  upper  lip,  and  from  their 
distribution  are  called  Labial.  The  most  internal  of  these  fas- 
ciculi terminate  on  the  skin,  the  muscles,  and  the  beginning  of 
the  mucous  membrane  of  the  nose,  where  they  anastomose  with 
the  extremities  of  the  internal  nasal  nerve.  The  middle  fasci- 


458  NERVOUS  SYSTEM. 

culi  go  to  the  muscles  of  the  upper  lip  and  the  skin  of  the  lat- 
ter, and  to  its  mucous  glands.  The  external  fasciculi  go  to  the 
zygomatic  muscles  and  to  the  contiguous  skin.  All  the  fore- 
going branches  of  the  infra-orbitar  nerve  anastomose  with  the 
extremities  of  the  fascial,  and  are  so  minutely  distributed  to  the 
skin  and  muscles  of  the  face,  that  it  would  require  a  very  pro- 
tracted description  to  point  them  out  particularly. 

The  Ptery go-palatine  Nerve  (Nervus  Pterygo-palatinus]  de- 
scends, as  a  single  or  a  double  trunk,  from  its  root  to  the  out- 
side of  the  spheno-palatine  foramen,  and  there  forms  the  gang- 
lion of  Meckel,*  or  the  spheno-palatine  ganglion,  the  existence 
of  which  is  not  constant.  From  this  ganglion,  or  from  the  nerve 
itself  proceed  several  branches. 

A  filament,  described  by  Bock,  is  detached  from  it,  which 
enters  into  the  sphenoidal  sinus  to  be  distributed  on  its  lining 
membrane,  and  sometimes  to  anastomose  with  the  motor  exter- 
nus  oculi. 

Then  arise  the  spheno-palatine  branches,  which  enter  the  nose 
through  the  spheno-palatine  foramen,  and  are  distributed  upon 
the  mucous  membrane  of  its  septum  and  turbinated  portions, 
after  the  manner  described  in  the  account  of  the  nose. 

The  Vidian,  or  Pterygoid  Nerve  (Nervus  Vidianus,  recurrens, 
pterygoideus)  arises  from  the  inferior  part  of  the  ganglion,  and  is 
a  recurrent  branch,  which  goes  backwards  through  the  pterygoid 
foramen  of  the  sphenoid  bone.  From  it  there  arise  some  fila- 
ments, which  get  to  the  mucous  membrane  about  the  anterior 
orifice  of  the  Eustachian  Tube,  either  through  the  spheno-pala- 
tine foramen,  or  by  small  foramina  in  the  pterygoid  process  of  the 
sphenoid  bone.  They  are  sometimes  united  into  a  single  trunk, 
called  pharyngeal,  by  Bock.  The  Vidian  nerve,  while  still  in 
its  canal,  then  divides  into  two  trunks,  the  superficial,  and  the 
deep  petrous. 

The  Superficial  Petrous  (Nervus  Petrosus  Superficialis)  tra- 
verses the  cartilaginous  matter  at  the  point  of  the  petrous  bone, 
in  the  anterior  foramen  lacerum  of  the  basis  of  the  cranium, 

*  Discovered  by  Meckel,  1749. 


NERVUS  TRIGEMINUS.  459 

gets  there  into  the  cavity  of  the  latter,  continues  its  progress 
backwards  on  the  superior  face  of  the  petrous  bone,  in  a  gntter 
marked  on  the  bone,  and  disappears  through  the  Vidian  fora- 
men. It,  in  a  short  space,  reaches  the  aqueduct  of  Fallopius, 
and  then  continues  to  adhere  to  the  facial  nerve  till  the  latter 
almost  reaches  the  stylo-mastoid  foramen:  it  then  abandons 
the  facial  nerve,  and,  as  mentioned  in  the  account  of  the  ear, 
traverses  the  tympanum  under  the  name  of  chorda  tympanij 
and,  finally,  emerging  at  the  glenoid  foramen,  it  runs  to  asso- 
ciate itself  with  the  lingual  branch  of  the  trigeminus.  The  su- 
perficial petrous,  in  the  early  part  of  its  course,  at  the  point  of 
the  petrous  bone,  detaches  one  or  more  filaments  to  the  sym- 
pathetic in  the  carotid  canal. 

The  Deep  Petrous  (Nervus  Petrosus  Profundus)  is  larger 
than  the  other.  It  also  penetrates  through  the  cartilaginous 
matter  at  the  point  of  the  petrous  bone,  and  enters  the  cavity 
of  the  cranium  under  the  dura  mater.  It  then  advances  to  the 
internal  carotid  artery,  and  anastomoses  there  with  a  filament 
from  the  motor  externus.  This  anastomosis  is  commonly  called 
the  beginning  of  the  sympathetic  nerve. 

The  Palatine  Nerve  (Nervus  Palatinus]  proceeds  from  the 
inferior  part  of  the  ganglion  of  Meckel,  and  gets  to  the  soft 
palate  of  the  mouth  through  the  posterior  palatine  foramen.  In 
this  course,  it  detaches  several  filaments  to  the  Schneiderian 
membrane,  which  reach  it  either  through  the  spheno-palatine 
foramen,  or  by  perforating  the  nasal  lamella  of  the  palate  bone. 
These  are  described  in  the  account  of  the  nose. 

The  trunk  of  the  palatine  nerve,  having  reached  the  r*oof  of 
the  mouth,  bends  forwards,  and  is  divided  into  many  filaments, 
some  of  which  are  distributed  along  the  gums  of  the  upper  jaw, 
others  are  distributed  on  the  lining  membrane  of  the  hard  pa- 
late and  upon  its  mucous  glands. 

There  are  two  other  nerves,  which  arise  either  immediately 
from  the  palatine,  or  from  the  ganglion  of  Meckel,  and  go  to 
supply  the  soft  palate.  They  are  called  the  smaller  palatine. 
One  of  them,  having  proceeded  for  a  short  distance  in  the  pos- 


460  NERVOUS  SYSTEM. 

terior  palatine  canal,  departs  from  it  in  a  little  canal  of  its  own, 
which  opens  behind  the  hook  of  the  internal  pterygoid  process. 
It  then  radiates  into  filaments,  which  supply  the  tonsil  gland 
and  the  muscular  and  membranous  structure  of  the  soft  palate. 
The  other  smaller  palatine  also  traverses,  after  the  same  man- 
ner, its  own  canal,  and  is  likewise  distributed  to  the  tonsil  gland 
and  to  the  soft  palate. 


Third  Branch  of  the  Trigeminus. 

The  Third  Branch  of  the  Trigeminus  (Nervus  Inframaxil- 
laris]  is  the  largest  of  the  three.  It 'arises  from  the  posterior 
inferior  part  of  the  ganglion  of  Gasser,  and  having  anastomosed 
with  the  cavernous  ganglion  of  the  sympathetic  nerve  by  fila- 
ments, which  are  not  constant,  it  emerges  from  the  cranium 
through  the  foramen  ovale  of  the  sphenoid  bone.  A  portion 
of  this  branch,  as  mentioned,  does  not  enter  into  the  composi- 
tion of  the  ganglion  of  Gasser,  but  proceeds  immediately  from 
the  pons  varolii. 

The  inferior  maxillary  nerve,  at  its  exit  from  the  foramen 
ovale,  is  covered  by  the  pterygoideus  externus  muscle,  and 
commonly  divides  there  into  two  branches,  one  anterior  and 
the  other  posterior. 

The  anterior  branch,  which  is  much  smaller  than  the  other, 
radiates  into  five  fasciculi;  the  masseter  nerve;  the  two  tem- 
poral; the  buccal;  and  the  pterygoid. 

a.  The  Masseter  Nerve  is. directed  horizontally  outwards 
and  backwards,  along  the  external  margin  of  the  pterygoideus 
externus,  and  in  front  of  the  temporo-maxillary  articulation: 
it  leaves  some  filaments  with  the  latter,  and  then  passing  be- 
tween the  insertion  of  the  temporal  and  of  the  external  ptery- 
goid muscle,  over  the  concave  edge  of  the  bone,  between  the 
condyle  and  the  coronoid  process  of  the  lower  jaw,  it  passes 
into  the  substance  of  the  masseter  muscle,  and  is  distributed 
through  it. 

b.  The  two  Temporal  branches  arise  by  a  common  fascicu- 
lus, but  sometimes  differently.     They  pass  outwards,  horizon- 
tally, between  the  external  pterygoid  muscle  and  zygomatic 


NERVUS  TRIGEMINUS.  461 

fossa.  They  then  ascend  on  the  side  of  the  temporal  bone,  be- 
tween it  and  the  temporal  muscle,  and  are  distributed  through 
the  latter  by  a  great  number  of  filaments.  Some  of  these  fila- 
ments penetrate  the  aponeurosis,  to  anastomose  with  the  super- 
ficial temporal  nerves.  And  one  of  them  anastomoses  with 
that  branch  qf  the  superior  maxillary  which  sends  filaments  to 
the  lachrymal  gland,  and  afterwards  escapes  from  the  orbit, 
through  the  foramina  in  the  malar  bone,  into  the  temporal  fos- 
sa. It  is  at  the  latter  place  that  the  anastomosis  occurs. 

c.  The  Buccal  Branch  is  the  largest  of  the  five.     It  advances 
between  the  pterygoid  muscles,  to  which  it  furnishes  a  few  fila- 
ments, and  then  descends  between  the  temporal  and  external 
pterygoid  muscle  to  the  posterior  part  of  the  buccinator.     It  is 
principally  distributed  on  the  latter,  upon  the  buccal  glands, 
and  the  corresponding  part  of  the  lining   membrane  of  the 
mouth.     Some  of  its  branches  advance  under  the  integuments 
of  the  face,  as  far  as  the  commissure  of  the  lips  to  the  muscles 
there,  and  anastomose  with  the  facial  nerve. 

d.  The  Pterygoid  Branch  is  the  smallest,  and  is  distributed 
principally  on  the  internal  pterygoid  muscle. 

The  posterior  branch  of  the  inferior  maxillary  nerve  is  so 
large,  that  it  looks  like  a  continuation  of  the  trunk.  It  is  di- 
vided into  the  superficial  temporal,  the  inferior  dental,  and  the 
lingual  nerve. 

a.  The  Superficial  Temporal  Branch  is  formed  by  a  union  of 
two  fasciculi,  between  which  passes  the  middle  artery  of  the 
dura  mater;  the  inferior  of  these  fasciculi  comes  from  the  infe- 
rior dental  nerve.  The  nerve  is  directed  outwardly,  and  winds 
horizontally  around  the  posterior  face  of  the  neck  of  the  con- 
dyle  of  the  lower  jaw,  between  it  and  the  meatus  auditorius  ex- 
ternus.  It  is  there  divided  into  several  small  fasciculi,  two  or 
three  of  which  penetrate  into  the  substance  of  the  parotid  gland, 
and  anastomose  with  the  facial  nerve  or  its  ramifications;  one  or 
two  others  go  backwards,  penetrate  between  the  bony  and  the 
cartilaginous  meatus  to  the  auditory  canal,  and  are  dispersed 
by  fine  filaments  upon  the  concha,  and  the  meatus  externus. 
According  to  Bock,  one  of  these  filaments  supplies  the  mem- 
brane of  the  tympanum,  and  also  anastomoses  with  the  chorda 
VOL.  II.— 59 


462  NERVOtS  SYSTEM. 

tympani.  Another, branch  of  the  superficial  temporal,  which 
is  the  largest  of  any,  traverses  the  parotid  gland,  and  thereby 
becomes  superficial,  just  in  front  of  the  external  ear.  It  then 
divides  into  filaments,  which  follow  the  course  of  the  superfi- 
cial temporal  artery,  and  thereby  supply  the  middle  part  of 
the  integuments  on  the  side  of  the  head.  It  anastomoses  with 
the  filaments  of  the  frontal  nerve,  and  with  those  of  the  occi- 
pital.. 

b.  The  Inferior  Dental  Nerve  is  placed  between  the  other 
two  branches,  and  exceeds  them  in  size.  It  descends  between 
the  two  pterygoid  muscles,  towards  the  posterior  mental  fora- 
men. Just  above  the  latter  it  detaches  a  small  branch,  the  mylo- 
hyoid,  which  occupies  the  small  gutter  on  the  bone  leading 
downward  from  the  posterior  mental  foramen.  This  branch 
sends  a  filament  to  the  submaxillary  gland,  then  passes  between 
the  anterior  belly  of  the  digastric  muscle  and  the  mylo-hyoi- 
deus,  to  both  of  which  it  gives  filaments,  and  finally  winding 
over  the  base  of  the  lower  jaw  in  front,  it  is  lost  upon  the  mus- 
cles of  the  chin. 

The  inferior  dental  nerve  then  enters  the  posterior  mental 
foramen,  and  divides  into  two  branches,  which  run  parallel 
with  one  another,  through  the  canal  in  the  middle  of  the  spongy 
structure  of  the  bone,  and  send  a  great  number  of  anastomotic 
filaments  to  each  other.  One  of  the  branches,  the  dental,  properly 
speaking,  as  it  passes  along  the  ends  of  the  roots  of  the  teeth, 
detaches  a  filament  to  each  root,  from  the  last  grinder  to  the 
first  incisor  tooth  inclusively:  it  also  sends  a  filament  to  the  gum 
intermediate  to  every  two  teeth.  All  of  these  filaments  arise 
from  the  dental  nerve,  at  places  behind  the  points  of  destina- 
tion; so  that  they  have,  before  reaching  the  latter,  to  run  for- 
wards and  upwards  through  little  canals  in  the  cellular  struc- 
ture of  the  bone. 

The  other  branch  of  the  inferior  dental  nerve  is  the  mental; 
it  does  not  advance  so  far  forward  in  the  bone  as  the  preceding, 
but  issues  from  it  at  the  anterior  mental  foramen,  and  immedi- 
ately is  divided  into  two  fasciculi,  the  inferior  labial  nerves. 
The  internal  fasciculus  is  distributed  by  filaments  upon  the 
muscles  of  the  chin  and  lower  lip,  the  contiguous  lining  mem- 
brane of  the  mouth  and  the  labial  glands.  The  external  fas- 


NERVUS  TRIGEMINUS.  463 

ciculus  rises  upwards  and  is  distributed  on  the  muscular  struc- 
ture, about  the  under  part  of  the  commissure  of  the  lip,  and 
to  the  contiguous  lining  membrane  and  glands  of  the  mouth. 

c.  The  Lingual  Nerve  descends  in  company  with  the  infe- 
rior dental,  but  in  advance  of  it,  and  diverging  slightly.  While 
between  the  two  pterygoid  muscles  it  receives  the  chorda  tym- 
pani  at  a  very  acute  angle.  It  then  passes  towards  the  side  of 
the  root  of  the  tongue,  deeply  concealed  by  the  angle  of  the 
lower  jaw,  and  above  the  submaxillary  gland,  to  which  it  gives 
some  considerable  filaments.  Occasionally,  however,  a  gan- 
glion, called  the  maxillary,  is  formed  here  by  one  or  more  fila- 
ments of  the  lingual  nerve,  and  from  this  ganglion  proceed  fila- 
ments to  the  submaxillary  gland. 

The  lingual  nerve  then  proceeds  forwards  between  the  mylo- 
hyoideus  and  the  hyo-glossus  muscle,  and  between  the  sublin- 
gual  gland  and  the  latter,  having  in  front  of  it  the  excretory 
duct  of  the  submaxillary  gland.  It  anastomoses  frequently 
with  the  hypoglossal  nerve,  sends  several  filaments  to  the  lining 
membrane  of  the  mouth,  below  the  tongue,  and  to  the  sublin- 
gual  gland.  It  then  divides,  or  radiates,  into  seven  or  eight 
fasciculi,  which  run  upwards  and  forwards  on  the  side  of  the 
stylo-glossus  muscle,  and  the  genio-hyo-glossus,  and  are  finally 
spent  by  very  fine  filaments  penetrating  into  the  structure  of 
the  papillae,  on  the  upper  surface  of  the  tongue. 

The  third  branch  of  the  trigemirius,  according  to  Dr.  Arnold, 
forms,  by  several  filaments,  a  ganglion  near  the  foramen  ovale. 
This  ganglion  is  below  the  spinous  process  of  the  sphenoid 
bone,  and  sends  off  several  filaments:  one  contributes  to  the  ner- 
vous anastomosis  of  Jacobson,*  which  connects  the  pterygoid, 
sympathetic,  and  glosso-pharyngeal  nerves:  the  other  filament 
passes  to  the  tensor  tympani,  and  is  distributed  upon  it.  Other 
filaments  join  the  superficial  temporal  nerve;  that  part  of  it 
which  supplies  the  membrana  tympani.  There  is  also  an  anas- 
tomosis with  the  portio  mollis.t 

*  This  nervous  anastomosis  is  described,  page  449,  article  Vidian  Nerve, 
f  Am.  Med.  Jour.  vol.  v.  p,  192. 


464  NERVOUS  SYSTEM. 


SECT.  VII.  -  NERVUS  FACIAL1S. 

The  Facial  Nerve  (Nervus  Facialis;  portio  dura  septimi; 
par  septimum)  having  gained  the  meatus  auditorius  internus, 
passes  in  front  of  the  auditory  nerve  into  the  canal  of  Fallopius, 
and  winding  through  it,  around  the  tympanum,  it  emerges  at 
the  stylo-mastoid  foramen,  having  sent  in  this  course  one  or 
more  filaments  to  the  muscles  of  the  little  bones  of  the 


panum. 

Afterwards,  the  facial  nerve  gives  off  several  branches,  which 
are  distributed  as  follows:  — 

a.  The  Posterior  Auricular  (Auricularis  Posterior]  arises 
/iear  the  stylo-mastoid  foramen,  as  stated  in  the  account  of  the 
Nerves  of  the  Ear;  and  having  sent  several  filaments  into  the 
mastoid  process,  it  winds  over  the  anterior  face  of  the  base  of 
the  latter,  and  divides  into  two  fasciculi.     The  anterior  is  dis- 
tributed in  filaments  upon  the  back  of  the  external  ear,  the  car- 
tilaginous meatus,  and  the  posterior  aurrs  muscle;  the  posterior 
ascends  upon  the  mastoid  portion  of  the  temporal  bone  to  the 
posterior  belly  of  the  occipito-frontalis  muscle,  and  is  spent 
by  filaments  to  the  latter,  and  to  the  corresponding  integu- 
ments, anastomosing  likewise  wit(i  ramifications  of  the  occipi- 
tal nerve. 

b.  The  facial  nerve  .then  detaches  filaments  to  the  muscles 
of  the  styloid  process,  and  to  the  posterior  belly  of  the  digas- 
tric muscle.     It  also  sends  filaments  of  anastomosis  to  the  su- 
perior part  of  the  sympathetic  nerve;  to  the  cutaneous  cervical; 
and  to  ramifications  of  the  glosso-pharyngeal,  of'  the  pneumo- 
gastric,  and  of  the  accessory. 

The  facial  nerve,  having  given  off  the  foregoing  filaments  and 
branches,  penetrates  downwards  and  forwards  into  the  substance 
of  the  parotid  gland,  where  it  rs  divided  into  a  number  of 
branches,  varying  from  two  to  five,  which  form  a  plexus  by 
their  anastomosis.  This  plexus  is  re-enforced,  as  mentioned, 
by  branches  from  the  superficial  temporal  of  the  inferior  max- 
illary, which  wind  around  the  neck  of  the  lower  jaw.  It  is 


NERVUS  FACIALIS.  466 

then  distributed  to  the  side  of  the  face  in  radiating  clusters  or 
columns  of  filaments,  called  the  temporo-facial,  the  buccal,  and 
the  cervico-facial. 

The  Temporo-Facial  Nerves,  or  Branches,  are  hid,  for  som'e 
distance,  in  the  upper  part  of  the  parotid  gland,  which  they 
traverse  below  the  neck  of  the  lower  jaw.  They  divide  into 
filaments,  some  of  which  go  to  the  temple,  and  others  to  the 
cheek.  The  temporal  branches  are  commonly  two  or  three  in 
number;  they  leave  filaments  with  the  parotid  gland,  mount 
over  the  zygoma,  and  are  distributed  to  the  anterior  auris  mus- 
cle, to  the  outer  section  of  the  orbicularis  palpebrarum,  and  to 
the  integuments  of  the  temple;  they  anastomose  in  their  distri-* 
bution  with  each  other,  with  the  superficial  and  deep  temporal 
branches  of  the  inferior  maxillary  nerve,  and  with  the  frontal 
and  lachrymal  branches  of  the  ophthalmic.  The  malar  branches 
are  primitively,  also,  two  or  three  in  number:  they  cross  the 
malar  bone,  dividing,  subdividing,  and  anastomosing  again,  and 
are  spent  upon  the  integuments  and  muscles  of  this  part  of  the 
face.  They  also  anastomose  with  filaments  of  the  lachrymal 
nerve,  and  with  those  of  the  infra-'orbitar  nerve. 

The  Buccal  Branches  are  three  in  number,  sometimes  two 
only;  and  pass  across  the  masseter  muscle  under  the  skin.  The 
superior  anastomoses  with  the  temporo-facial,  and  the  inferior 
with  the  cervico-facial.  The  buccal  branches  supply  the  skin 
and  muscles  of  the  face  intermediate  to  the  eye  and  to  the  low-* 
er  lip.  The  numerous  filaments  into  which  they  divide  anas- 
tomose frequently  with  each  other,  and  with  the  branches  of 
the  fifth  pair,  which  appear  about  the  same  parts,  as  the  exter- 
nal  and  internal  nasal  nerve,  the  infra-orbitar,  and  so  on.  The 
middle  buccal  is  parallel  with  the  duct  of  the  parotid  gland,  and 
adheres  to  it. 

The  Cervico-Facial  Branch  descends  in  the  substance  of  the' 
parotid  gland,  behind  the  ramus  of  the  lower  jaw;  when  it 
reaches  the  angle  of  the  latter  it  goes  obli-quely  forwards,  be- 
neath the  platysma  myodes  muscle.  Though  it  sends  off  many 
fasciculi,  they  may  be  referred  to  two  divisions,  a  superior  and 
in  inferior.  The  first  crosses  the  inferior  part  of  the  masseter 
nuscle,  and  may  be  traced  in  its  numerous  distribution  of  fila- 
nents,  to  the  integuments  and  muscles  lying  upon  the  body  of 


466  NERVOUS  SYSTEM. 

the  lower  jaw.  These  filaments  anastomose  with  each  other, 
and  with  the  mental  branches  of  the  inferior  dental  nerve.  The 
inferior  division  supplies  the  skin  and  the  platysma  myodes 
muscle  on  the  upper  part  of  the  neck  along  the  base  of  the 
lower  jaw.  Its  filaments  are  joined  by  several  coming  from 
the  anterior  fasciculus  of  the  third  cervical  nerve. 

The  anastomoses  of  the  facial  nerve,  derived  from  its  own 
branches  and  from  those  of  the  trigeminus,  which  reach  the  face, 
are  entirely  too  numerous  for  a  detailed  description  of  them; 
it,  indeed,  appears  unnecessary  to  extend  the  latter  beyond  a 
certain  point.  The  most  satisfactory  account  has  been  pub- 
lished by  Meckel.* 

SECT.  VIII. — NERVUS  HYPOGLOSSUS. 

The  Hypoglossal  Nerve,  (Nervus  Hypoglossiis,  Lingualis,} 
having  arisen  from  the  medulla  oblongata,  and  escaped  from 
the  cranium  through  the  anterior  condyloid  foramen,  adheres 
closely  for  an  inch  to  the  pneumogastric  nerve.  It  descends 
between  the  external  carotid  artery  and  the  internal  jugular 
vein,  the  latter  being  behind  the  other;  and  then  winds  over 
the  carotid,  externally,  just  below  the  origin  of  the  occipital  ar- 
tery. It  is  there  covered  by  the  posterior  belly  of  the  digas- 
tricus  and  by  the  stylo-hyoideus.  It  then  passes  forwards  be- 
neath the  external  jugular  vein,  and  lower  down  somewhat  than 
the  tendon  of  the  digastric  muscle,  and,  finally,  ascends  to  the 
tongue,  being  covered  or  concealed  by  the  mylo-hyoideus  mus- 
cle. The  nerve  in  this  course,  from  the  external  carotid  to  the 
tongue,  forms  a  remarkable  curve,  the  convexity  of  which  is 
downwards. 

The  Hypoglossal,  while  adhering  to  the  par  vagum,  com- 
monly leaves  a  few  filaments  with  it.  As  it  crosses  the  ex- 
ternal carotid,  it  detaches  a  large  branch,  the  Ramus  Descen- 
dens  Noni,  which  goes  down  the  neck,  along  the  sheath  of 
the  carotid  artery  and  the  internal  jugular  vein,  in  front  of  the 
latter. 

*  J.  F.  Meckel,  de  Nervis  Faciei,  Mem,  de  1'Acad.  des  S.  de  Berlin,  1751, 
Caldani,  Tab.  247. 


NERVUS  HYPOGLOSSUS.  467 

The  ramus  descendens  has  been  heautifully  figured  by  Scar- 
pa,  in  his  Plates  of  the  Nerves.  According  to  him,  when  it 
has  got  about  half  way  down  the  neck,  but  still  resting  on  the 
sheath  of  the  vessels,  it  detaches,  in  front,  two  filaments,  which, 
after  the  course  of  an  inch  forwards,  unite,  and  then  separate 
again  to  be  distributed  to  the  upper  ends  of  the  omo-hyoid  and 
sterno-hyoid  muscles.  The  descendens  noni  then  forms,  an 
inch  lower  down,  a  small  gangliform  plexus,  resting  upon  the 
sheath  of  the  great  vessels  of  the  neck,  under  the  omo-hyoid 
muscle.  This  plexus  is  joined  by  two  fasciculi,  which  descend 
from  the  first  and  second  cervical  nerves,  and  from  it  pro- 
ceed downwards  and  backwards,  two  filaments,  which  join  the 
phrenic  nerve;  also,  one  to  the  lower  part  of  the  omo-hyoid 
muscle;  and  three  or  more,  which  are  divided  and  distributed 
upon  the  sterno-hyoid  and  thyroid  muscles,  and  upon  the  mus- 
cles of  the  larynx.  Meckel  states,  that  some  of  these  ramifica- 
tions, on  the  left  side  principally,  penetrate  to  the  thorax,  and 
reach  the  pericardium. 

The  hypoglossal  nerve,  having  sent  off  the  ramus  descendens, 
reaches  the  external  face  of  the  hyo-glossus  muscle,  and  is  there 
concealed  by  the  mylo-hyoideus,  where  it  gives  filaments  to  the 
muscles  of  the  larynx,  to  the  hyo-glossus,  genio-hyoideus,  and 
genio-hyo-glossus.  These  filaments  anastomose  frequently  with 
each  other,  and  in  two  or  three  places  at  the  anterior  part  of  the 
tongue  with  the  lingual  branch  of  the  nervus  trigeminus.  Af- 
ter these  branches  are  given  off,  the  trunk  of  the  hypoglossal 
nerve  penetrates  into  the  substance  of  the  genio-hyo-glossus 
muscle,  and  extends  itself  near  its  fellow,  and  not  far  from  the 
middle  line  of  the  tongue  to  the  point  of  the  latter.  It  first  dis- 
tributes filaments  near  the  posterior  part  of  the  tongue,  and 
then,  successively,  as  far  as  its  anterior  extremity.  They  can- 
not be  traced  to  the  papillae,  but  are  lost  upon  the  muscular 
structure. 

It  is  a  general  opinion  among  anatomists  that  the  hypo-glos- 
sal nerve  is  only  intended  to  excite  the  muscular  movements 
of  the  tongue.  The  opinion  is  founded  upon  the  circumstance 
of  its  filaments  not  reaching  the  papillae,  whereas  those  of  the 
lingual  branch  of  the  trigeminus  do.  Colombo  narrates  a  case, 


468  NERVOUS  SYSTEM. 

in  which  there  was  a  congenital  privation  of  taste,  where  the 
lingual  branch  of  the  trigeminus  was  distributed  upon  the  occi- 
put instead  of  upon  the  tongue,  which  goes  far  to  prove  the  dif- 
ference of  function  in  the  two  nerves. 


SECT.  IX. — NERVUS  ACCESSORIUS. 

The  Accessory  Nerve,  (Nervus  JZccessori us,  Willisii^  having 
arisen,  as  described,  from  the  cervical  medulla  and  the  medulla 
oblongata,  is  directed  outwards  to  the  posterior  foramen  lace- 
rum,  in  company  with  the  pneumogastric  or  par  vagum.  Some- 
times it  is  separated  from  it  in  its  passage  through  the  base  of 
the  cranium,  by  a  thin  partition  of  dura  mater;  on  other  occa- 
sions merely  by  a  fold  of  the  tunica  arachnoidea:  but  at  the  in- 
ferior part  of  this  foramen  it  adheres  so  closely  to  the  par.  va- 
gum that  the  two  look  like  but  one  nerve. 

Near  its  exit  it  is  divided  into  two  fasciculi.  The  most  in- 
ternal gives  off  one  or  two  filaments,  which,  joining  a  branch 
of  the  par  vagum,  forms  the  superior  pharyngeal  nerve;  the 
internal  branch  then  descends,  and  being  divided  into  several 
branches,  they,  successively,  join  the  upper  part  of  the  par 
vagum.  The  external  fasciculus  descends  for  two  inches  be- 
hind the  internal  jugular  vein,  being  placed  first  of  all  between 
it  and  the  occipital  artery,  but  subsequently  between  the  vein 
and  the  sterno-mastoid  muscle.  It  then  pierces  this  muscle 
about  one-third  of  the  length  of  the  latter  from  its  superior 
extremity,  and  leaves  filaments  in  it  which  anastomose  with 
some  from  the  third  cervical  nerve.  In  continuing  its  descent, 
it  is  re-enforced  and  augmented  considerably  in  volume,  by 
branches  from  the  second  and  third  cervical.  Having  reached 
the  anterior  margin  of  the  trapezius  muscle,  it  then  distributes 
itself  to  the  latter,  by  internal  and  by  external  branches. 

SECT.  X. NERVUS  GLOSSO-PHARYNGEU9. 

The  Glosso-Pharyngeal  Nerve  (Nervus  Glosso-Pharyngeus,) 
though  commonly  considered  as  distinct  from  the  pneumogas- 


NERVUS  ACCESSORIUS.  469 

trie,  has  so  many  connexions  with  it,  both  at  its  root,  in  its 
course  through  the  posterior  foramen  lacerum,  and,  in  its  dis- 
tribution, that  it  seems  like  a  part  or  branch  of  the  same.  At 
the  base  of  the  cranium  in  front  of  the  pneumogastric,  it  forms, 
according  to  some  anatomists,*  a  ganglion  of  five  or  six  lines 
in  length,  the  existence  of  which  was  denied  by  Bichat.  From 
this  ganglion  proceeds  a  filament,!  which  penetrates  into  the 
tympanum  and  divides  into  two  branches;  one  of  them  ascends 
along  the  promontory,  having  detached  a  filament  to  the  mem- 
brane of  the  foramen  rotundum:  it  then  penetrates  the  petrous 
bone;  and  anastomoses  or  joins  with  the  superficial  petrous 
nerve.  The  other  branch  passes  below  the  bony  Eustachian 
Tube,  and,  gaining  the  carotid  canal,  anastomoses  there  with  the 
Sympathetic  Nerve.  This  is  part  of  the  anastomosis  of  Jacob- 
son,  and  is  also  described  in  the  account  of  the  Vidian  Nerve. 
The  ganglion  also  gives  off  other  filaments,  which  traverse  the 
canal  of  the  dura  mater,  to  join  the  pneumogastric  nerve,  the 
accessory  and  the  sympathetic. 

On  issuing  from  the  posterior  foramen  lacerum,  the  glosso- 
pharyngeal  is  separated  from  the  pneumogastric  by  the  internal 
jugular  vein.  It  is  then  directed  downwards  and  forwards  be- 
tween the  internal  carotid  and  the  stylo-pharyngeus  muscle; 
afterwards  between  the  latter  and  the  stylo-glossus;  it  fol- 
lows the  direction  of  the  latter  to  the  side  of  the  root  of  the 
tongue. 

In  this  course,  it  sends  off  many  filaments.  Shortly  after 
leaving  the  cranium,  it  detaches  one  backwards  to  the  digas- 
tric branch  of  the  facial,  and  another  to  the  pneumogastric.  It 
then  sends  off  two  filaments,  which  descend  along  the  internal 
and  the  common  carotid,  and  are  divided  into  several  branches, 
some  of  which  anastomose  with  the  pharyngeal  branch  of  the 
pneumogastric,  others  descend  (fti  the  common  carotid  with 
filaments  from  the  pharyngeal  branch,  and  being  joined  by  two 
or  three  small  twigs  from  the  superior  cervical  ganglion,  they 
reach  the  lower  part  of  the  neck,  and  concur  in  the  forming 

*  Andersach  and  Huber.     This  ganglion  is  considered  by  some  as  commencing 
before  the  nerve  penetrates  the  foramen  lacerum. 
f  Rosenmuller,  Jacobson,  Lobstein. 

VOL.  II.— 60 


470  NERVOUS  SYSTEM. 

of  the  superficial  cardiac  nerve.  Farther  down  after  the  origin 
of  these  branches  the  glosso-pharyngeal  detaches  two  or  three 
filaments  to  the  stylo-pharyngeus  muscle,  as  well  as  some  to  the 
upper  and  middle  constrictors  of  the  pharynx,  to  the  pharyngeal 
plexus  of  the  sympathetic  and  pneumogastric,  and  to  the  pos- 
terior lateral  and  superficial  part  of  the  tongue. 

The  glosso-pharyngeal  nerve  having  got  between  the  stylo 
and  hyo-glossus  muscles,  is  placed  intermediately  to  the  lingual 
branch  of  the  fifth  pair  and  hypo-glossal  nerve.  Some  of  its 
branches  then  go  to  the  integuments  of  the  base  of  the  tongue, 
to  its  mucous  glands,  large  papillae,  and  may  be  traced  to  the 
mucous  membrane  of  the  soft  palate,  to  the  amygdalae,  and  to 
the  covering  membrane  of  the  epiglottis.  Others  go  into  the 
muscles  of  the  tongue,  and  others  may  be  traced  along  the  ex- 
ternal margin  of  the  tongue,  beneath  its  mucous  membrane  for 
some  distance.  Scarpa  has  delineated  a  remarkable  plexus, 
which  he  denominates  Circulus  Tonsilkris  Anderschii  or  Anas- 
tomosis Plexuosa,  formed  by  these  several  filaments  and  by 
branches  of  the  lingual,  on  the  side  of  the  root  of  the  tongue, 
at  the  base  of  the  tonsil  gland. 

SECT.  XI. NERVUS  PNEUMOGASTRICUS. 

The  Pneumogastric  Nerve  (Nervus  Pneumogastricus,  Vagus, 
Par  Octavum,  Decimum  of  Andersecti}  at  its  exit  from  the  cra- 
nium through  the  posterior  foramen  lacerum,  in  front  of  the  in- 
ternal jugular  vein,  is  closely  united  to  the  hypo-glossal,  glosso- 
pharyngeal,  and  accessory  nerves,  by  compact  cellular  substance. 
It  is  first  placed  in  front  of  the  hypo-glossal  nerve,  but,  in  a  short 
Space,  gets  behind  it,  and  is  also  separated  from  the  glosso-pha- 
ryngeal by  the  internal  jugular  vein.  Opposite  the  transverse 
process  of  the  atlas,  it  leaves  the  hypo-glossal  nerve,  and  as- 
sumes a  position  between  the  internal  carotid  and  the  internal 
jugular,  on  the  vertebral  side  of  these  vessels,  and  is  enveloped 
in  their  sheath  of  dense  cellular  substance.  It  maintains  this 
relative  position  along  the  common  carotid  to  the  root  of  the 
neck. 

At  the  latter  place,  the  pneumogastric  of  the  right  side  goes 
in  front  of  the  subclavian  artery,  near  its  root,  but  on  the  left 


PNEUMOGASTRIC  NERVE.  471 

side  it  crosses  the  root  of  the  left  subclavian  artery,  and  the  arch 
of  the  aorta  to  the  left  of  the  origin  of  the  left  carotid.  In  get- 
ting fairly  into  the  cavity  of  the  thorax,  it  is  directed  hackwards 
and  downwards  from  these  points,  towards  the  posterior  face  of 
the  bronchia,  between  it  and  the  pleura.  It  then  abandons  the 
bronchia,  and  applies  itself  to  the  oesophagus,  and  follows  it 
through  the  diaphragm  to  the  stomach.  The  nerve  of  the  left 
side,  in  its  course  along  the  oesophagus,  is  on  the  front  surface 
of  the  latter,  and  the  nerve  of  the  right  side,  on  its  posterior 
surface. 

The  pneumogastric  anastomoses  with  the  accessory  while 
passing  through  the  foramen  lacerum  posterius.  Somewhat 
lower  down,  it  also  anastomoses  with  the  glosso-pharyngeal  and 
with  the  superior  cervical  ganglion  of  the  sympathetic.  The 
branches  which  it  afterwards  sends  off,  go  to  the  neck  to  the 
viscera  of  the  thorax,  and  to  those  of  the  abdomen,  after  the  fol- 
lowing manner: — 

A.  Cervical  Branches.  The  Superior  Pharyngeal  Nerve 
(Ramus  Pharyngeus)  arises  just  below  the  preceding  anastomo- 
sis. It  is  directed  downwards  on  the  internal  face  of  the  inter- 
nal carotid,  and  having  sent  an  anastomotic  filament  to  the  glos- 
so-pharyngeal nerve,  it  forms  on  the  middle  constrictor  of  the 
pharynx,  the  pharyngeal  plexus  which  is  re-enforced  by  fila- 
ments from  the  superior  cervical  ganglion  of  the  sympathetic, 
from  the  glosso-pharyngeal,  and  from  the  superior  laryngeal 
nerve.  The  filaments  departing  from  this  plexus,  are  spent 
principally  upon  the  middle  constrictor,  but  a  few  of  them  also 
go  to  the  superior  constrictor;  and  others,  descending  along  the 
primitive  carotid,  anastomose  with  ramifications  from  the  glos- 
so-pharyngeal, and  from  the  superficial  cardiac  nerve.  A  fila- 
ment, called  the  inferior  pharyngeal,  sometimes  proceeds  from 
the  pneumogastric  a  little  below  the  other,  and  also  is  spent  upon 
the  pharynx. 

The  pneumogastric,  at  the  place  where  it  detaches  these  pha- 
ryngeal branches,  or  a  little  above  them,  becomes  softened  in 
its  texture,  enlarges  somewhat,  and  has  the  fasciculi  which 
compose  it  moderately  separated  by  a  sort  of  red  gelatinous 
substance  interposed  between  them.  This  portion  is  its  gang- 


472  NERVOUS  SYSTEM. 

liform  plexus,  and  into  it  is  joined  one  or  more  branches  from 
the  accessory  nerve. 

The  Superior  Laryngeal  Nerve  (Nervus  Laryngeus  Supe- 
rior) arises  from  the  gangliform  plexus.  It  descends  between 
the  internal  carotid  and  the  superior  cervical  ganglion,  anasto- 
mosing on  the  way  with  the  latter,  with  the  pharyngeal  plexus, 
and  the  hypo-glossal  nerve;  it  then  divides  into  an  external  and 
an  internal  laryngeal  branch.  The  former  sends  its  filaments 
to  the  muscles  situated  on  the  fore  part  of  the  thyroid  cartilage; 
lo  the  thyroid  gland;  and  some  of  them  penetrate  through  the 
crico-thyroid  membrane  to  the  lining  membrane  of  the  larynx. 
The  internal  laryngeal  branch  is  placed  above  the  other;  it  is 
directed  towards  the  thyreo-hyoid  membrane,  which  it  pene- 
trates and  then  begins  to  ramify.  Some  of  the  branches  go  to 
the  epiglottis  cartilage,  its  covering  membrane,  and  the  adjacent 
portion  of  the  lining  membrane  of  the  pharynx.  Other  branches 
are  distributed  to  the  small  muscles  which  move  the  arytenoid 
cartilages,  and  to  the  lining  membrane  of  the  larynx.  The  fila- 
ments which  go  to  the  epiglottis  have  an  arrangement  indicated 
by  Bichat;  that  of  going  into  the  foramina  which  perforate  it, 
but  they  cannot  be  traced  farther. 

The  pneumogastric  afterwards  does  not  send  off  any  regular 
branches  till  it  reaches  the  lower  part  of  the  neck.  It  then 
detaches  two  or  three  filaments,  (rami  cardiaci,)  which,  on  the 
right  side,  have  their  roots  about  an  inch  above  the  subclavian 
artery,  and  on  the  left  side,  an  inch  lower  down.  On  the  right 
side,  they  descend  along  the  subclavian  and  the  arteria  innomi- 
nata,  on  the  left  along  the  left  carotid;  they  reach  the  arch  of 
the  aorta,  and  in  their  course,  as  well  as  there,  anastomose  very 
freely  with  the  superficial  cardiac  nerve.  The  rami  cardiaci 
are  frequently  more  abundant  on  the  right  side  than  on  the  left. 

The  Inferior  Laryngeal  Nerve  (Nervus  Laryngeus  Inferior, 
Recurrens)  is  a  considerable  branch  of  the  pneumogastric,  which 
comes  off  next  to  the  cardiac.  On  the  right  side  it  arises  im- 
mediately after  the  trunk  has  passed  between  the  subclavian 
artery  and  the  subclavian  vein.  It  then  winds  around  the  sub- 
clavian artery  so  as  to  retain  the  latter  in  its  loop;  having  thus 


PNEUMOGASTRIC  NERVE.  473 

got  behind  the  artery,  it  then  ascends  towards  the  larynx,  on 
the  side  of  the  trachea,  covered  by  the  common  carotid  and  by 
the  inferior  thyroid  artery. 

In  this  course  the  inferior  laryngeal  nerve  detaches  the  fol- 
lowing branches:  1.  From  the  convexity  of  its  loop  it  sends 
filaments  to  the  assistance  of  the  cardiac  branches  just  spoken 
of,  arising  from  the  pneumogastric,  and  to  those  coming  from 
the  inferior  cervical  ganglion  of  the  sympathetic.  2.  It  de- 
taches the  pulmonary  branches,  the  origin  of  which  is  compli- 
cated with  the  plexus  of  nerves  existing  about  their  roots;  these 
descend  in  front  of  the  trachea,  reach  the  pulmonary  artery, 
and  follow  its  ramifications  into  the  lungs;  some  of  the  fila- 
ments, however,  go  to  the  cardiac  plexus.  3.  The  inferior 
laryngeal  then  sends  many  filaments  to  the  oasophagus;  4. 
Branches  which  go  to  the  inferior  part  of  the  thyroid  gland; 
5.  Filaments  to  the  trachea,  some  of  which  penetrate  the  mem- 
brane on  its  posterior  part,  others  go  between  the  cartilages; 
they  are  then  distributed  to  the  lining  membrane  and  to  the 
mucous  glands  of  the  part.  6.  The  inferior  laryngeal  nerve  is 
then  distributed  in  branches  to  the  inferior  constrictor  of  the 
pharynx  and  its  lining  membrane,  but  the  most  of  its  termi- 
nating filaments  penetrate  to  the  larynx,  between  the  thyroid 
and  the  cricoid  cartilage,  and  are  lost  upon  the  lining  membrane 
of  the  larynx,  and  upon  the  small  muscles  which  move  the  ary- 
tenoid  cartilages.  These  terminating  filaments  anastomose  with 
such  as  come  from  the  superior  laryngeal  nerve. 

It  is  generally  stated  by  anatomists  that  the  distribution  of 
the  inferior  laryngeal  nerve  to  the  larynx,  is  confined  to  the 
thyreVarytenoid,and  posterior  and  lateral  crico-arytenoid  mus- 
cles. Mr.  G.  Rainy,  states,  in  the  London  Medical  Gazette, 
that  he  has  repeatedly  traced  its  filaments,  also,  to  the  trans- 
verse and  oblique  arytenoid.*  The  recurrent  of  the  left  side 
forms  a  much  larger  loop  than  the  other,  and  arises  lower  down, 
inasmuch  as  it  has  to  wind  around  the  arch  of  the  aorta,  at  the 
origin  of  the  left  subclavian  artery;  with  some  inconsiderable 
exceptions,  its  course  and  distribution  afterwards  are  precisely 
the  same  with  those  of  the  nerve  of  the  right  side. 

*  Am.  Med.  Journ.  vol.  iv.  p.  198. 


474  NERVOUS  SYSTEM. 

B.  The  Thoracic  Branches  of  the  pneumogastric  are  as  fol- 
low: The  inferior  tracheal  nerves  come  from  it  just  below  the 
recurrent:  they  are  five  or  six  in  number;  some  of  them  go  in 
front  of  the  trachea  and  bronchia,  and  others  behind  them. 
They  are  complicated  by  anastomoses  with  the  branches  of  the 
recurrent  nerve,  and  with  those  of  the  inferior  cervical  ganglion, 
and  form  a  small  plexus,  denominated  the  anterior  pulmonary, 
which  lies  upon  the  front  of  the  root  of  the  lung,  and  has  its 
filaments  following  the  branches  of  the  pulmonary  artery 
through  the  lung.  The  posterior  filaments  supply  the  structure 
of  the  bronchia  by  penetrating  it,  and  some  of  them  go  to  join, 
the  posterior  pulmonary  plexus. 

As  the  pneumogastric  gets  behind  the  trachea  and  the  bron- 
chia, it  is  sensibly  enlarged  and  somewhat  flattened,  the  cohe- 
sion of  its  fasciculi  being  somewhat  looser.  Several  filaments 
depart  there  from  it,  which  form  an  intertexture  with  each  olher; 
some  of  them  pass  inwards,  to  be  distributed  on  the  bronchia, 
trachea,  and  resophagus.  Others,  which  are  given  off  as  the 
nerve  lies  upon  the  posterior  face  of  the  root  of  the  lung, 
amounting  to  six  or  seven  in  number,  but  being  of  various 
sizes,  run  transversely  outwards,  and  form  an  intertexture  with 
one  another.  The  latter  are  joined  by  filaments  from  the  infe- 
rior cervical  and  the  first  dorsal  ganglion  of  the  sympathetic, 
and  thus  constitute  the  posterior  pulmonary  plexus.  The  fila- 
ments from  this  plexus  follow  the  distribution  of  the  bronchia, 
and,  according  to  Bichat,  are  all  destined  to  the  mucous  mem- 
brane and  the  mucous  glands  of  the  lung;  as  they  may  be  traced 
piercing  successively  the  ramifications  of  the  bronchia,  in  order 
to  reach  its  lining  membrane. 

On  the  right  side,  the  par  vagum,  while  furnishing  the  pul- 
monary plexus,  and  for  some  distance  lower  down,  is  divided 
into  from  four  to  six  considerable  fasciculi,  which  form  with 
each  other  a  plexus  or  series  of  anastomoses,  having  very  large 
meshes,  and  from  which  proceed  many  filaments  to  the  oesopha- 
gus. Afterwards  these  fasciculi  are  assembled  into  a  single 
chord,  which  proceeds  on  the  posterior  face  of  the  ossophagus, 
along  with  it  into  the  abdomen. 

On  the  left  side,  the  par  vagum,  after  forming,  the  posterior 
pulmonary  plexus,  is  split  into  two  or  three  fasciculi;  which 


SYMPATHETIC  NERVE.  475 

likewise  furnish  branches  to  the  oesophagus,  and  unite  to  form 
a  single  chord,  which  proceeds  on  the  front  surface  of  the  oeso- 
phagus, along  with  it  into  the  abdomen. 

The  two  nerves,  while  descending  in  this  way,  send  frequent 
anastomotic  filaments  to  each  other,  and  to  the  oesophagus. 

C.  In  the  Abdomen  the  par  vagum  is  distributed  as  follows: 
Filaments  are  sent  from  each  nerve,  which  form  a  plexus  around 
the  cardiac  orifice  of  the  stomach.  The  right  nerve  is  then 
divided  into  many  branches;  some  are  distributed  on  the  poste- 
rior face  of  the  stomach;  others  go  along  the  lesser  curvature 
of  this  viscus,  and  reach  thereby  the  pylorus,  where  they  anas- 
tomose with  filaments  from  the  left  nerve,  and  from  the  gastric 
plexus  of  the  sympathetic;  others  go  behind  the  stomach  to  join 
the  solar  plexus,  and  are  blended  with  the  latter  in  its  distribu- 
tion to  the  liver,  vena  portarum,  duodenum,  and  pancreas.  The 
left  par  vagum,  being  placed  in  front  of  the  cardia,  is  resolved 
into  several  radiating  filaments  or  fasciculi,  some  of  which  sup- 
ply the  anterior  face  of  the  stomach,  others  go  along  its  lesser 
curvature  to  the  pylorus,  to  anastomose  with  the  right  nerve 
and  the  gastric  branches  of  the  sympathetic,  and  are  finally 
blended,  after  the  same  manner  as  the  preceding,  with  the  so- 
lar plexus. 


CHAPTER  II. 


OF  THE  SYMPATHETIC  NERVE.* 


THE  Sympathetic  Nerve  (Nervus  Sympatheticus  Magnus, 
Intercostalis  Maximus,  Gangliosits,)  differs,  in  a  great  num- 
ber of  respects,  from  every  other  nerve  of  the  body;  and  if  we 
were  actuated  only  by  its  peculiarities,  with  Bichat,  Meckel, 
and  others,  we  might  with  great  propriety,  set  it  apart  as  some- 


*  Anton.  Scarpa,  Tabul.  Neurolog, 


476  NERVOUS  SYSTEM. 

thing  having  a  claim  to  an,  insulated  description  and  location. 
The  dissection  of  it,  however,  is  so  much  blended  with  that 
of  the  par  vagum,  that  the  descriptions  of  the  two  go  best 
hand  in  hand;  and  are,  therefore,  most  conveniently  studied 
together. 

This  nerve  consists  in  a  series  or  chain  of  ganglions,  extend- 
ing from  the  base  of  the  cranium  to  the  lower  end  of  the  sac- 
rum. They  are  placed  on  the  lateral  part  of  the  bodies  of  the 
vertebrae,  are  united  to  each  other  by  intermediate  nervous 
chords,  and  send  off  continually  filaments  to  the  adjacent  organs. 
With  the  exception  of  the  neck,  there  is  a  ganglion  for  each 
intervertebral  space,  both  of  the  true  vertebra  and  sacrum.  Be- 
sides these  ganglions,  there  are  others  which  are  situated 
around  the  trunks  of  some  of  the  large  vessels  of  the  abdomen. 

The  superior  extremity  of  the  sympathetic  nerve,  opposite 
to  the  transverse  process  of  the  second  cervical  vertebra,  and 
behind  the  internal  carotid  artery,  forms  a  ganglion,  which,  for 
the  purpose  of  description,  may  be  considered  as  the  first  of  the 
series.  This  ganglion  is  the  superior  cervical.  The  nervus 
motor  externus  oculi,  in  passing  through  the  cavernous  sinus, 
and  the  Vidian  nerve,  in  passing  by  the  point  of  the  petrous 
bone,  both  send  a  filament  downwards  through  the  carotid  canal; 
which  two  filaments  unite  to  form  a  single  chord,  that  runs 
into  the  superior  extremity  of  this  ganglion.  The  filament 
from  the  Vidian  nerve  is,  as  mentioned,  the  deep  petrous  nerve. 
The  common  view  taken  by  anatomists  of  this  nervous  con- 
nexion is,  that  it  is  the  beginning  of  the  sympathetic,  though 
by  Bichat  it  is  described  as  the  termination,  or  one  of  its  ex- 
tremities. The  distinction,  though  important  physiologically, 
is  less  so  when  the  object  is  simply  to  describe  the  course  and 
anatomical  relations  of  this  nerve,  as  they  may  be  equally  un- 
derstood by  either  mode  of  description. 

The  branch  from  the  motor  externus  most  frequently  forms, 
on  the  external  face  of  the  internal  carotid,  in  the  cavernous 
sinus,  a  ganglion,  (Ganglion  Cavernosum,  Caroticum,)  dis- 
covered by  Laumonier,  which  is  sometimes  made  by  several 
filaments,  from  the  motor  externus,  instead  of  one.  M.  Lob- 


SYMPATHETIC  NE&VE.  477 

stein,  in  his  Essay  on  the  Sympathetic,  has  attributed  this 
ganglion  to  the  deep  petrous  nerve,  in  which  I  think  he  is 
mistaken.*  From  the  ganglion  cavernosum,  it  has,  of  late, 
been  ascertained  that  filaments  may  be  traced  to  the  ganglion 
of  Gasser,  (Plexus  Gangliformis,)  of  the  trigeminus,  to  the 
pituitary  gland,  to  the  infundibulum;  and,  moreover,  a  fasciculus 
which,  according  to  H.  Cloquet,  forms  a  plexus  around  the 
ophthalmic  artery,  and  may  be  traced  along  all  its  branches, 
even  the  central  artery  of  the  retina.  This  plexus  anastomoses 
with  the  lenticular  ganglion,  and  consequently  establishes  a  di- 
rect nervous  communication  between  the  sympathetic,  the  mo- 
tor externus  oculi,  and  first  branch  of  the  fifth  pair.  The  know- 
ledge of  this  connexion  has  caused  anatomists  to  locate  the  len- 
ticular ganglion  and  the  ciliary  nerves  in  the  ganglionic  system 
of  the  sympathetic,  as  forming  a  part  of  the  latter. 

The  sympathetic,  in  descending  the  neck,  is  placed  behind 
the  carotid  artery  and  internal  jugular  vein.  It  is  common- 
ly said  to  be  enclosed  in  the  sheath  of  these  great  vessels,  but 
the  statement  is  loose  and  inaccurate,  as  it  is  fastened  to  the 
front  surface  of  the  longus  colli  muscle  by  cellular  substance 
distinct  from  the  sheath,  as  may  be  manifested  by  pushing 
a  knife  handle  between  them  and  raising  up  the  sheath.  The 
chord  which  comes  down  from  the  carotid  canal  is  close  to 
the  pneumogastric  and  hypoglossal  nerves.  Having  formed 
the  first  cervical  ganglion,  it  descends  as  mentioned;  and,  op- 
posite to  the  space  between  the  fifth  and  sixth  cervical  ver- 
tebrae, it  is  again  enlarged  into  the  Middle  Cervical  Ganglion, 
which  is  much  smaller  and  more  irregular  than  the  first. 
The  sympathetic  is  then  traced  with  some  difficulty,  in  con- 
sequence of  the  numerous  branches  coming  from  it;  but,  with 
attention,  a  trunk  may  be  found  as  the  continuation  of  it.  This 
trunk  passes  to  the  interval  between  the  head  of  the  first  rib 
and  the  transverse  process  of  the  last  cervical  vertebra,  and 
there  enlarges  into  another  ganglion,  called  Inferior  Cervical, 
or  First  Dorsal. 

To  understand  well  the  connexions  of  the  sympathetic  in  the 

*  De  Nerv.  Sympathetic.    Paris,  1823, 

VOL,  II.— 61 


47S  NERVOUS  SYSTEM. 

neck,  each  of  the  cervical  ganglions  must  be  studied  particu- 
larly. 

1st.  The  Superior  Cervical  Ganglion  varies  considerably  in 
its  extent;  commencing  very  generally  opposite  to  the  second 
cervical  vertebra,  it  is  sometimes  elongated  to  the  lower  part 
of  the  third  and  even  of  the  fourth.  In  cases  of  unusual  elon- 
gation, it  is  smaller  than  in  others. 

It  sends  off,  from  its  external  margin,  several  filaments,  about 
four,  which  cross  the  anterior  face  of  the  rectus  anticus  major 
muscle,  and  terminate  by  anastomosing  with  the  anterior  fasci- 
culi of  the  occipital  nerve  and  of  the  three  first  cervical:  when 
the  ganglion  is  short,  the  two  lower  filaments  come  from  the 
sympathetic  below  it,  instead  of  from  the  ganglion. 

Several  filaments  also  proceed  from  this  ganglion  to  the  con- 
tiguous muscles  on  the  vertebral  column,  to  the  pharynx,  to  the 
larynx,  and  to  the  thyroid  gland. 

This  ganglion  also  sends  off  what  are  called  its  Anterior 
branches,  which  are  peculiar  for  their  reddish  colour  and  for 
their  softness;  the  latter  quality  has  obtained  for  them  the  name 
of  Nervi  Molles.  They  may  be  referred,  by  their  position,  to 
three  orders.  The  superior  ascends  to  anastomose  with  the 
pneumogastric,  hypoglossal,  and  facial  nerves,  near  their  exit 
from  the  cranium.  The  middle  are  two  or  three  in  number, 
but  immediately  divide  into  many  filaments,  forming  the  caro- 
tid plexus  by  assistance  from  the  pneumogastric,  glosso-pha- 
ryngeal,  and  facial  nerves.  Some  of  the  branches  of  this  plex- 
us descend  behind  the  primitive  carotid,  at  the  place  of  its  bi- 
furcation, and  accompany  it  to  its  origin,  continually  interlacing 
with  each  other.  Others  surround,  after  the  same  manner,  the 
external  carotid,  and  subdivide  into  a  plexus  for  each  of  its 
branches,  so  that  very  fine  filaments  may  be  traced  along  the 
superior  thyroidal,  the  lingual,  facial,  occipital,  and  temporal 
arteries.  These  nerves  are,  for  the  most  part,  difficult  to  trace, 
from  their  extreme  tenuity.  The  primitive  branches,  from 
which  these  plexuses  come,  are  sometimes  previously  united 
into  a  small  ganglion,  which  serves  as  a  common  centre  to  all 
these  nervous  irradiations.  The  third  order  of  anterior  branches, 
amounting  to  from  four  to  six,  come  either  from  the  ganglion 


THE  SYMPATHETIC  NERVE.  479 

or  from  the  sympathetic  just  below  it.  The  chord  formed  by 
their  union,  called  the  Superficial  Cardiac  Nerve,  descends  on 
the  external  side  of  the  primitive  carotid,  anastomosing  with 
filaments  from  the  pneumogastric  and  from  thedescendens  noni. 
It  gives  small  ramifications  to  the  contiguous  parts,  as  to  the 
pharynx,  oesophagus,  the  sterno-hyoid  and  thyroid  muscles.  It 
terminates  in  the  lower  part  of  the  neck,  by  detaching  anasto- 
mosing branches  to  the  branches  of  the  recurrent  nerve;  some 
of  them  also  go  along  the  inferior  thyroid  artery  to  the  thy- 
roid gland.  What  remains  of  it  is  lost  in  the  middle  cardi- 
ac nerve;  for  it  cannot  be  traced,  in  an  insulated  and  distinct 
manner,  to  the  heart;  from  which  cause,  its  appellation  is  ob- 
jectionable. 

2.  The  Middle  Cervical  Ganglion,  placed  intermediately  to 
the  fifth  and  sixth  cervical  vertebrae,  upon  the  longus  colli  mus- 
cle, is  there  concealed  by  the  common  carotid,  the  internal  ju- 
gular vein,  and  the  pneumogastric  nerve.  It  is  sometimes  de- 
ficient: according  to  Meckel,  in  the  proportion  of  once  in  three 
times.  In  my  own  dissections  I  have  always  found  it,  though 
under  various  circumstances  of  size  and  form.  It  is  more  flat- 
tened than  the  preceding,  and  never  so  long.  Sometimes  it  is 
double.  Like  the  preceding,  it  has  a  great  many  filaments  at- 
tached to,  or  emanating  from  it. 

The  external  filaments,  amounting  to  about  three  in  number, 
pass  from  it  to  the  anterior  fasciculi  of  the  fourth,  fifth,  and  sixth 
cervical  nerves,  between  the  origins  of  the  scaleni  muscles. 
Some  of  •  its  filaments  accompany  the  inferior  thyroid  artery, 
and,  along  with  the  superficial  cardiac,  form  a  plexus  around  it, 
which  reaches  to  the  thyroid  gland. 

The  Middle  Cardiac  Nerve  is  formed  by  several  of  the  ante- 
rior branches,  collecting  into  a  single  chord.  The  latter  de- 
scends along  the  external  side  of  the  primitive  carotid,  crosses, 
on  the  right  side  of  the  body,  the  root  of  the  subclavia^n  artery, 
and  then  going  along  the  posterior  face  of  the  arteria  innomina- 
ta,  it  gets  between  the  aorta  and  the  bifurcation  of  the  trachea, 
where  it  is  merged  in  the  commencement  of  the  cardiac  plexus 
of  nerves.  On  the  left  side,  the  middle  cardiac  nerve  is  formed 
by  an  assemblage  of  filaments  from  the  middle  and  inferior  cer- 


480  NERVOUS  SYSTEM. 

vical  ganglions,  which  descend  along  the  left  subclavian  artery 
to  the  aorta,  and  are  joined,  on  the  front  of  the  latter,  by  the  su* 
perficial  cardiac  nerve.  On  both  sides,  these  cardiac  nerves 
form  intricate  anastomoses  with  the  pneumpgastric  nerve  and 
its  recurrent  branch. 

3.  The  Inferior  Cervical  Ganglion,  situated  as  mentioned, 
near  the  head  of  the  first  rib,  like  the  others,  is  subject  to  vari- 
ations in  its  form  and  size.  Several  filaments  may  be  traced 
between  it  and  the  middle  cervical  ganglion.  One  penetrates 
into  the  canal  of  the  transverse  processes  along  with  the  verte- 
bral artery,  and,  forming  a  plexus  around  it,  may  be  traced  dis- 
tributing branches  to  the  heads  of  the  contiguous  muscles,  as 
high  up  as  the  second  cervical  vertebra. 

The  external  branches  of  the  inferior  cervical  ganglion  are 
numerous  and  small.  Some  of  them  anastomose  with  the  ante- 
rior fasciculi  of  the  two  or  three  inferior  cervical  and  the  first 
dorsal  nerve.  Others  form  a  plexus  around  the  subclavian  ar- 
tery, and  follow  the  latter,  in  its  distribution,  to  the  upper  ex- 
tremity and  to  the  shoulder. 

The  anterior  branches  of  this  ganglion  concur,  after  some 
anastomoses  with  each  other,  to  form  a  single  chord,  the  Infe- 
rior Cardiac  Nerve,  which  goes,  on  the  right  side,  along  the  ar- 
teria  innominata,  to  be  blended  with  the  cardiac  plexus.  On 
the  left  side,  it  is  not  so  distinct,  but  is  blended  with  the  mid- 
dle cardiac  nerve,  and  forms  its' inferior  root. 


Of  the  Cardiac  Plexus  of  the  Sympathetic- 

The  Cardiac  Plexus  (Plexus  Cardiacus)  is  situated  between 
the  arch  of  the  aorta,  and  the  lower  part  of  the  trachea  and  the 
bronchiae,  and  extends  from  the  division  of  the  pulmonary  ar- 
tery to  the  commencement  qf  the  arteria  innominata.     It  is 
formed,  almost  wholly,  from  the  branches  sent  by  the  three 
cervical  ganglions  of  the  sympathetic  of  each  side,  and  prin- 
cipally from  that  of  the  middle  one,  or  the  middle  cardiac  nerve. 
The  filaments  which  come  from  the  recurrent  nerve  and  the 


THE  SYMPATHETIC  NERVE.  481 

par  vagum  are  blended  into  the  cardiac  plexus  in  such  a  man- 
ner that  they  cannot  be  traced  immediately  to  the  heart.  It 
is  worthy  of  remark,  that  the  three  cardiac  nerves  of  the  right 
side  are  more  constantly  found  than  the  same  number  on  the 
left,  in  consequence  of  the  lower  one  of  the  latter  soon  merging 
itself,  after  its  origin  into  the  middle  cardiac  nerve  of  that 
side. 

The  cardiac  plexus  is  formed  by  the  common  assemblage  of 
the  nerves  from  the  two  sides  of  the  neck,  and  is  therefore 
single.  From  this  plexus  arise  all  the  nerves  which  go  to  the 
heart,  so  that  in  tracing  them  the  distinction  between  right  and 
left  is  confounded.  Scarpa,  has  pointed  out,  in  this  circum- 
stance, an  analogy  between  them  and  the  nerves  which  supply 
the  abdominal  viscera. 

The  cardiac  plexus  is  distinguished  by  the  softness  of  its  tex- 
ture. For  the  purpose  of  description,  its  branches  may  be  di- 
vided into  Anterior,  Posterior,  and  Inferior. 

The  Anterior  Branches  are  but  few.  They  are  found  on  the 
front  of  the  arch  of  the  aorta.  One  of  them  crosses  it  on  the  right 
side  of  the  arteria  innominata;  others  cross  it  from  the  root  of 
the  left  carotid  and  subclavian,  downwards.  In  both  cases,  se- 
veral of  the  terminating  filaments  run  into  the  anterior  corona- 
ry plexus.* 

The  Posterior  Branches  are  more  numerous;  but  run  only  a 
short  course,  when  they  are  merged  in  the  anterior  pulmonary 
plexus  formed  by  the  par  vagum. 

The  Inferior  Branches  are  the  largest  and  the  most  abundant. 
Some  of  them  follow  the  pulmonary  artery  until  its  entrance 
into  the  lungs,  others  are  distributed  upon  the  pulmonary  veins; 
but  the  greater  number  of  them  are  arranged  into  two  plexuses 
called  Coronary,  from  their  observing  the  course  of  the  corona- 
ry arteries.  The  posterior  coronary  plexus  is  larger  than  the 
other.  It  reaches  the  base  of  the  heart,  along  the  pulmonary 
artery,  and  has  its  filaments  distributed  principally  to  the  left 

*  Scarpa. 


482  NERVOUS  SYSTEM. 

auricle  and  left  ventricle,  observing  the  course  of  the  left  coro- 
nary artery  and  of  its  branches.  The  anterior  coronary  plexus 
gets  in  front  of  the  heart,  between  the  aorta  and  the  pulmonary 
artery.  It  anastomoses  freely  at  its  superior  part  with  the 
other,  and  is  then  distributed  to  the  right  auricle  and  ventricle, 
along  the  course  of  the  right  coronary  artery  and  of  its  branches. 

Of  the  Thoracic  Ganglions  of  the  Sympathetic. 

These  ganglions  are  twelve  in  number,  and  are  placed  on  or 
near  the  heads  of  the  ribs,  at  the  commencement  of  each  inter- 
costal space,  and  are  only  covered  by  the  pleura.  Their  shape 
is  irregular,  and  they  differ  also  in  size,  being  always  smaller 
than  the  cervical  ganglions.  The  chord  of  the  sympathetic  is 
continued,  successively,  from  one  ganglion  to  another,  so  that 
they  form  a  complete  chain  by  their  connexion  with  each  other. 

From  each  ganglion  there  proceeds  one  or  more  external 
branches  which  go  outwards  to  anastomose  with  the  intercostal 
nerve  of  the  corresponding  part.  Each  ganglion  also  detaches 
one  or  more  internal  branches  or  filaments  to  the  adjacent  parts 
lying  on  the  vertebral  column:  some  go  to  the  cellular  substance, 
•others  to  the  longus  colli  muscle,  others  to  the  aorta,  others  to 
the  cardiac  and  to  the  pulmonary  plexuses.  Among  these  in- 
ternal branches  there  are  several  which  concur  to  form  the 
Splanchnic  Nerves,  of  which  there  are  two;  the  Great  and  the 
Small. 

The  Great  Splanchnic  Nerve  arises,  by  filaments,  from  the 
sixth  to  the  ninth  or  tenth  thoracic  ganglions,  inclusively;  one 
or  more  filaments  coming  from  each  ganglion.  They  are  di- 
rected downwards  and  forwards  on  the  sides  of  the  dorsal  ver- 
tebra, covered  by  the  pleura,  and  unite,  successively,  into  a 
trunk  about  the  eleventh  dorsal  vertebra.  This  trunk  penetrates 
into  the  cavity  of  the  abdomen,  between  the  middle  and  the  in- 
ternal head  of  the  lesser  muscle  of  the  diaphragm,  and  some- 
times by  the  opening  for  the  aorta. 

Having  got  into  the  abdomen,  the  great  splanchnic  divides 
into  several  fasciculi,  which  diverging  from  each  other,  are  con- 
cealed on  the  right  side  by  the  liver,  and  on  the  left  by  the  sto- 


THE  SYMPATHETIC  NERVE.  483 

mach.  On  each  side  of  the  aorta  there  is  a  large  ganglion 
formed  by  an  assemblage  of  several  smaller  ones;  it  is  called  the 
Serai-lunar.  Into  it  terminate,  for  the  most  part,  these  fasciculi: 
some  of  them,  however,  go  immediately  into  the  solar  plexus, 
which  emanates  from  the  semi-lunar  ganglion. 

The  Small  Splanchnic  Nerve  is  derived,  by  filaments,  from 
the  tenth  and  the  eleventh  thoracic  ganglions.  Having  united, 
they  penetrate  the  crus  of  the  diaphragm,  and,  reaching  the  ab- 
domen, the  trunk  is  divided  into  two  branches,  of  which  the 
uppermost  ascends  to  join  the  great  splanchnic  before  its  divi- 
sion, and  the  lower  descends  to  join  the  renal  plexus. 

Besides  these  two  splanchnic  nerves,  it  frequently  happens 
that  there  are  others  which  come  from  the  eleventh  and  twelfth 
thoracic  ganglions,  and  from  the  communicating  branch  between 
the  last  thoracic  and  the  first  lumbar.  They  unite  into  a  trunk 
which  goes  to  the  renal  plexus,  and  have  been  called,  by  Walterr 
the  Posterior  Renal  Nerves. 


Of  the  Solar  Plexus. 

The  Semi-lunar  Ganglion,  situated,  as  mentioned,  on  the  side 
of  the  aorta,  is  somewhat  semicircular  or  oval,  and  is  about  an 
inch  long;  its  form,  however,  is  much  diversified  in  different 
subjects.  The  several  ganglions  of  which  it  is  composed,  are 
frequently  fused  into  a  single  one.  That  of  the  right  side  is 
more  voluminous  than  the  other,  and  is  placed  between  the  as- 
cending vena  cava  and  the  crus  of  the  diaphragm,  somewhat 
above  the  right  renal  artery.  That  of  the  left  is  situated  upon 
the  left  crus  of  the  diaphragm,  somewhat  below  the  splenic  ar- 
tery. Between  their  inferior  extremities,  there  are  generally 
two  or  three  smaller  ganglions. 

These  several  ganglions  are  united  by  numerous  filaments, 
which  send  out  many  ramifications,  and  anastomose  freely  with 
each  other. 

The  preceding  arrangement  may  be  considered  as  the  root 
of  the  solar  plexus,  which  extends  from  the  coeliac  artery  to  the 
lower  margin  of  the  emulgents,  and  as  it  is  common  to  the 
ganglions  of  the  two  sides,  it  is  an  inch  and  a  half  or  two  inches 


484  NERVOUS  SYSTEM. 

wide.  Bichat  has  very  properly  remarked,  that  this  plexus 
seems  to  exist  for  the  aorta,  as  all  the  divisions  which  it  sends 
out  follow  so  exactly  the  branches  of  this  artery,  that  we  are 
forced  to  adopt  the  latter  as  the  basis  of  the  description.  The 
intertexture  and  the  number  of  the  branches  emanating  from  the 
solar  plexus  are  so  complicated,  that  a  description  of  individual 
branches  would  be  almost  endless,  as  well  as  unintelligible;  ana- 
tomists are,  therefore,  generally  agreed  to  describe  the  plexus 
according  to  the  order  of  the  arteries  which  its  detachments  ad- 
here to  and  surround. 

1.  The  Diaphragmatic  Plexus  consists  of  a  few  filaments 
coming  from  the  superior  part  of  the  solar,  and  following  the 
course  of  the  phrenic  arteries.     Some  of  them  anastomose  with 
the  terminating  filaments  of  the  phrenic  nerve,  in  the  thickness 
of  the  diaphragm. 

2.  The  Plexus  ivhich  surrounds  the  Coeliac  rfrtery,  like  it, 
is  quickly  disposed   into  three   divisions,  which   follow   the 
branches  of  this  artery. 

a.  The  Superior  Coronary  Plexus  of  the  stomach,  is  the 
smallest   of  the   three.     It   attends   the   corresponding  artery 
along  the  lesser  curvature  of  the  stomach  to  the  pylorus,  sup- 
plying the  stomach  continually  with  very  fine  filaments.     In 
its  course,  it  anastomoses  with  the  par  vagum,  and  sends  fila- 
ments to  the  hepatic  plexus. 

b.  The  Hepatic  Plexus  is  the  largest  of  the  three.     It  sur- 
rounds the  hepatic  artery  and  the  vena  portarum,  and,  in  its 
course,  detaches  branches  which  go  with  the  right  gastro-epi- 
ploic  artery  to  the  great  curvature  of  the  stomach,  and  constitute 
the  inferior  coronary  plexus.     Branches  are  also  sent  to  the  pan- 
creas and  to  the  duodenum.     The  hepatic  plexus  then  enters 
the  transverse  fissure  of  the  liver,  and  its  branches  may  be 
traced  to  the  several  lobes  and  to  the  gall-bladder. 

c.  The  Splenic  Plexus  is  but  small,  and  surrounds  the  sple- 
nic artery.     The  few  branches  of  which  it  is  composed,  anasto- 


SYMPATHETIC!  NERVfc'. 

mose  but  rarely  with  each  other.  Some  of  them  are  distri- 
buted upon  the  pancreas,  along  with  the  pancreatic  branches  of 
the  splenic  artery;  others  go  with  the  left  gastro-epiploic  ar- 
tery to  the  left  extremity  and  to  the  greater  curvature  of  the 
stomach;  the  remainder  penetrate  into  the  substance  of  the 
spleen,  through  its  fissure,  along  with  the  branches  of  the  sple- 
nic artery. 

3.  The  Superior  Mesenteric  Plexus  is  derived  from  the  so- 
lar, near  the  superior  mesenteric  artery;  it  descends  some  short 
distance  on  the  aorta,  before  it  reaches  the  latter.     It  passes 
with  the  artery  between  the  pancreas  and   the  duodenum,  and 
is  then  included  between  the  two  laminae  of  mesentery;  it  is 
then  distributed,  by  very  numerous  filaments,  along  with  the 
branches  of  the  artery,  to  the  whole  of  the  small  intestines,  to 
the  coecum,  and  to  the  ascending  and  transverse  colon. 

4.  The  Renal  Plexus,  one  on  each  side,  is  derived  from  the 
lower  lateral  part  of  the  solar.     Two  or  three  ganglions,  on  the 
root  of  the  renal  artery,  contribute  to  it,  and  it  is  also  re-en- 
forced  by  an  addition  from  the  lesser  splanchnic  nerve.     The 
branches  which  form  this  plexus  do  not  anastomose  much,  till 
they  get  near  the  kidney;  they  then  penetrate  into  its  substance, 
through  the  fissure.     Some  filaments  from  this  plexus  go  to  the 
capsule  renales:  others  follow  the  course  of  the  spermatic  arte- 
ry, and  constitute  the  spermatic  plexus  which  goes  to  the  testi- 
cle in  the  male,  and  to  the  ovarium  in  the  female. 

5.  The  Inferior  Mesenteric  Plexus  is  a  continuation  of  the 
solar,  on  the  anterior  face  of  the  abdominal  aorta.     It  is  much 
smaller  than  the  superior  mesenteric  plexus,  though  it  receives 
continually,  in  its  descent,  filaments  from  the  lumbar  gangli- 
ons of  the  sympathetic.     It  forms  frequent  anastomoses  around 
the  root  of  the  inferior  mesenteric  artery,  and  near  the  superior 
strait  of  the  pelvis,  is  resolved  into  two  columns  of  fibres.   One 
column  is  distributed  along  with  the, artery  to  the  rectum,  to 
the  sigmoid  flexure  of  the  colon,  and  to  the  left  section  of  the 
latter,  thereby  anastomosing  with  the  colic  branches  of  the  su* 

VOL.  IL— 62 


486  NERVOUS  SYSTEM. 

perior  mesenteric  plexus.  The  other  column  descends  into  the 
pelvis,  in  front  of  the  sacrum,  and  contributes  to  form  the  hy- 
pogastric  plexus,  but  several  of  its  branches  also  follow  the  ex- 
ternal and  the  internal  iliac  arteries. 


Of  the  Lumbar  Ganglions  of  the  Sympathetic. 

These  ganglions  are  five  in  number,  on  either  side,  and  are 
placed  anteriorly  on  the  sides  of  the  bodies  of  the  lumbar  ver- 
tebrae, near  the  anterior  margin  of  the  psoas  magnus  muscle. 
Their  form  is  irregular;  they  are  smaller  than  the  cervical  gan- 
glions, but  larger  than  the  dorsal. 

The  last  thoracic  ganglion  is  united  to  the  first  lumbar  by  a 
small  branch,  which  may  be  considered  as  the.  continuation  of 
the  sympathetic.  A  deficiency  of  this  branch  has,  however, 
been  several  times  observed  by  anatomists;  also  a  deficiency  in 
the  connecting  nervous  chord  of  the  ganglions  below.  The  gan- 
glions themselves  are  inconstant  in  their  number,  being  some- 
times less  than  five;  they  vary  likewise  in  their  situation.  It 
is  to  be  understood,  however,  that- in  a  majority  of  subjects,  the 
sympathetic  goes  on  uninterruptedly  from  one  ganglion  to  ano- 
ther, sometimes  by  one  branch;  on  other  occasions,  by  two  or 
three. 

Each  lumbar  ganglion  sends  outwards  one  or  more  external 
branches,  which  applying  themselves  to  the  body  of  the  conti- 
guous vertebra,  reach  the  corresponding  intervertebral  foramen 
of  the  loin?,  and  join  with  the  anterior  branch  of  the  corre- 
sponding lumbar  nerve.  Some  of  these  external  branches  are 
spent  upon  the  quadratus  lumborum  muscle. 

Each  lumbar  ganglion,  or  the  intermediate  chord  of  the  sym- 
pathetic, also  detaches  branches  internally,  which  are  very  small, 
and  more  or  less  interwoven  with  each  other.  These  branches 
get  to  the  abdominal  aorta,  and,  joining  the  inferior  mesenteric 
plexus  upon  it,  are  distributed  along  with  the  latter. 


THE  SYMPATHETIC  NERVE.  487 


Of  the  Sacral  Ganglions  of  the  Sympathetic. 

There  are  generally  three  of  these  ganglions  which  may  be 
readily  found:  sometimes  four  or  five.  They  are  situated  in 
a  line,  on  the  anterior  face  of  the  sacrum,  near  the  correspond- 
ing foramina  for  the  transmission  of  the  sacral  nerves;  and  are 
united  with  each  other  by  intermediate  fibres,  from  one  to  three 
in  number,  which  are  the  continuation  of  the  sympathetic  nerve. 
Bichat  asserts,  that  frequently  the  first  of  these  ganglions  is 
not  united  to  the  last  of  the  lumbar  by  an  intermediate  nerve, 
so  that  there  the  continuity  of  the  sympathetic  is  interrupted. 

Each  ganglion  sends  off,  externally,  one. or  more  filaments, 
by  which  it  is  united  to  the  corresponding  sacral  nerve:  it  also 
detaches  filaments  in  this  direction  to  the  pyriformis  and  the 
levator  ani  muscles. 

Each  ganglion  likewise  detaches,  from  its  internal  margin, 
ramifications,  which  go  obliquely  downwards  on  the  front  of 
the  sacrum,  and  anastomose  with  corresponding  filaments  from 
the  opposite  side. 

From  these  ganglions  many  branches  pass  forwards  to  the 
hypogastric  plexus;  which  is  formed  by  them,  by  the  inferior 
mesenteric  plexus,  and  by  a  great  many  filaments  from  the  lower 
sacral  nerves,  principally  the  third.  This  plexus  is  distributed 
upon  the  rectum,  the  bladder,  vesiculse  seminales,  and  prostate 
of  the  male;  and,  in  place  of  the  two  latter  in  the  female,  upon 
the  vagina  and  the  uterus. 

The  last  sacral  ganglion  detaches  downwards  one  or  more 
filaments,  which  lie  upon  the  front  of  the  os  coccygis,  and 
anastomose  with  the  corresponding  filaments  from  the  other 
side,  to  form  a  sort  of  arch,  the  convexity  of  which  is  down- 
wards. In  this  manner,  terminates  the  chord  of  the  sympa- 
thetic nerve. 


488  NERVOUS  SYSTEM. 


CHAPTER  III. 


OF  THE  NERVES  OF  THE  MEDULLA  SP1NALIS. 

THE  nerves  of  the  medulla  spinalis,  with  the  exception  of 
the  first,  which,  from  its  position,  is  generally  called  the  Sub- 
occipital  by  anatomists,  are  arranged  into  cervical,  dorsal,  lum- 
bar, and  sacral,  according  to  the  order  of  the  inter-vertebral 
foramina,  through  which  they  pass  out:  but  a  much  better 
division  would  be  Cervical,*  Thoracic,  and  Abdominal.  Their 
mode  of  origin,  and  the  ganglions  formed  by  them,  have  been 
pointed  out  in  the  account  of  the  medulla  spinalis. 

SECT.  I. — OF  THE  UPPER  NINE  SPINAL  NERVES. 

These  are  spent  upon  the  neck,  upon  the  upper  extremities, 
and  upon  the  diaphragm.  They  consist  in  the  Sub-occipital 
Nerve,  the  Cervical,  and  the  First  Dorsal. 

Of  the  Sub-occipital  Nerve. 

The  Sub-occipital  Nerve  (Nervus  Infra-occipitalis,  decimits 
cerebri]  is  one  of  the  smallest  that  proceeds  from  the  medulla 
spinalis.  It  has  the  peculiarity,  generally,  of  arising  by  a  single 
root,  which  comes  from  the  anterior  chord  of  the  medulla  spi- 
nalis, between  the  occiput  and  the  first  cervical  vertebra.  This 
root  consists  of  from  two  to  six  or  seven  fasciculi,  situated  one 
above  another.  When  the  posterior  root  exists,  it  is  very 
small,  is  composed  of  from  one  to  three  fasciculi,  and  anasto- 
moses with  the  accessory  nerve. 

The  trunk  of  this  nerve  passes  from  the  vertebral  cavity 
through  the  foramen  formed  in  the  dura  mater  by  the  vertebral 

•  In  this  case,  the  term  Cervical  would  include  the  first  eight. 


UPPER  NINE  SPINAL  NERVES.  489 

artery;  it  goes  out  below  the  latter,  and  between  the  occiput 
and  the  first  vertebra,  behind  its  superior  oblique  process.  It 
there  forms  a  small  long  ganglion,  like  the  other  spinal  nerves, 
and  then  divides  into  an  anterior  and  a  posterior  fasciculus. 

The  anterior  fasciculus  is  the  smaller  of  the  two;  it  follows, 
in  some  measure,  the  course  of  the  vertebral  artery,  and  going 
forwards  to  the  front  of  the  transverse  process,  is  then  divided 
into  several  fine  filaments,  some  of  which  go  to  the  contiguous 
muscles  on  the  front  of  the  vertebrae;  others  join  themselves 
to  the  pneumogastric  and  hypoglossal  nerves,  and  to  the  supe- 
rior cervical  ganglion  of  the  sympathetic;  others  anastomose 
with  the  first  cervical  nerve. 

The  posterior  fasciculus  runs  backwards,  and  is  distributed 
to  the  recti  and  the  obliqui  muscles  on  the  back  of  the  neck  and 
to  the  complexus. 

Of  the  Cervical  Nerves. 

These  are  seven  in  number:  the  'first  one  gets  frorrTthe 
spinal  cavity  between  the  atlas  and  the  dentata,  and  the  last 
betweeg  the  seventh  cervical  and  the  first  dorsal  vertebra. 
After  the  ganglion  is  formed  upon  the  posterior  fasciculus  of 
each,  the  trunk,  made  by  the  union  of  the  two  fasciculi,  di- 
vides almost  immediately  again  into  an  anterior  and  a  posterior 
trunk. 

Of  the  First  Cervical  Nerve. 

The  posterior  trunk  is  the  largest,  and  goes  directly  back- 
wards. It  has  its  filaments  distributed  to  many  of  the  mus- 
cles on  the  upper  posterior  part  of  the  cervical  vertebrae,  and 
to  the  integuments  of  the  part.  Some  of  the  branches  ascend 
through  the  muscles,  near  the  occiput;  and,  rising  up  on  the 
latter,  are  distributed  upon  its  integuments,  and  upon  the  occi- 
pito-frontalis  muscle. 

The  anterior  trunk  is  directed  forwards  under  the  inferior 
oblique  muscle  of  the  neck,  and  then  divides  into  two  branches: 
the  superior  joins  the  anterior  branch  of  the  sub-occipital  nerve, 
and  anastomoses  with  the  first  cervical  ganglion  of  the  sym- 


490  NERVOUS  SYSTEM. 

pathetic,  and  with  the  par  vagum  and  the  hypoglossarnerve; 
the  inferior  joins  the  anterior  branch  of  the  second  cervical 
nerve. 

Of  the  Second  Cervical  Nerve. 

This  nerve  issues  between  the  second  and  the  third  cervical 
vertebra.  Its  posterior  trunk  is  spent  upon  the  trapezius,  corn- 
plexus,  and  other  muscles  on  the  back  of  the  neck,  and  upon 
the  integuments  of  the  latter;  it  also  anastomoses  with  the  pos- 
terior trunk  of  the  nerve  above  and  below. 

The  anterior  branch  or  trunk  detaches,  first  of  all,  some  small 
filaments  to  the  muscles  on  the  front  of  the  cervical  vertebrae; 
it  then  divides  into  two  principal  fasciculi,  one  of  which  ascends 
and  the  other  descends. 

The  ascending  branch  goes  upwards  and  backwards,  and 
early  in  its  course  anastomoses  with  the  first  cervical  nerve, 
thereby  forming  with  it  a  nervous  noose;  it  then  mounts  upon 
the  occiput,  and  is  distributed  upon  the  parts  on  the  latter 
region,  anterior  to  the  occipital  branches  of  the  preceding 
nerve. 

The  descending  branch  turns  over  the  posterior  margin  of 
the  sterno-cleido  mastoideus  muscle,  and  gives  filaments  to  it. 
It  is  distributed  afterwards  by  branches,  some  of  which  go  to 
the  integuments  of  the  middle  and  inferior  parts  of  the  neck, 
(nervi  subcutanei  colli  medii  et  inferiores;)  others  go  to  the 
integuments  of  the  neck  upon  the  angle  and  the  base  of  the 
lower  jaw,  (nervi  subcutanei  superiores;)  and  one  to  the  ex- 
ternal ear,  (nervus  auricularus  cervicalis. ) 

From  the  anterior  fasciculus  of  the  second  cervical  nerve, 
there  proceeds  a  filament  downwards,  which  is  the  upper  root 
of  the  phrenic  nerve;  another  filament  from  it  joins  the  superior 
cervical  ganglion  of  the  sympathetic. 

Of  the  Third  Cervical  Nerve. 

This  nerve  comes  out  between  the  third  and  the  fourth  cer- 
vical vertebra.  Its  posterior  fasciculus  is  distributed  to  the  mus- 


UPPER  NINE  SPINAL  NERVES.  491 

cles  on  the  back  of  the  cervical  vertebrae,  and  to  the  integu- 
ments of  the  part;  anastomosing,  by  its  branches,  with  the  nerve 
above  and  below. 

The  anterior  fasciculus  is  larger  than  the  posterior,  and  goes 
obliquely  downwards  and  outwards  at  first;  it  sends  anastomo- 
tic  branches  to  the  nerve  above  and  below;  it  also  anastomoses 
with  the  superior  cervical  ganglion  of  the  sympathetic  and  with 
the  descendens  noni.  One  of  its  branches,  being  joined  by  the 
branch  just  spoken  of,  from  the  second  cervical  nerve,  consti- 
tutes the  root  of  the  phrenic  nerve.  But  the  principal  number 
of  its  branches  are  distributed  to  the  integuments  along  the  cla- 
vicle, (nervi  supra-clavicular  es,)  the  upper  part  of  the  sternum, 
and  the  shoulder;  some  of  them  going  into  the  contiguous  mus- 
cles, as  the  trapezius,  subclavius,  &c.  Several  anastomoses  exist 
between  the  branches  of  this  nerve  and  the  terminating  branches 
of  the  nervus  accessorius. 

The  three  preceding  cervical  nerves  form,  by  their  anasto- 
moses with  each  other,  a  plexus,  consisting  in  a  number  of  large 
loops  or  arches,  which  lie  upon  the  sides  of  the  muscles  con- 
nected with  the  transverse  processes  of  the  cervical  vertebrae. 
There  are  commonly  two  series  of  anastomoses:  the  branches 
of  the  first,  form  the  second  series,  and  from  the  latter  proceed, 
for  the  most  part,  the  several  branches  which  have  been  de- 
scribed. These  anastomoses  are  covered  by  the  upper  half  of 
the  sterno-cleido  mastoid  muscle,  are  involved  in  the  cellular 
membrane  surrounding  the  great  vessels  of  the  neck,  and  are 
covered  by  the  lympathetic  glands.  Their  intertexture  and  dis- 
tribution are  such,  that  no  adequate  idea  of  them  can  be  con- 
veyed without  dissection.  From  this  plexus  several  branches 
go  to  the  sterno-mastoid  muscle,  and  it  is  united  above  to  the 
sub-occipital  nerve  and  below  to  the  fourth  cervical. 

Of  the  Phrenic  Nerve. 

The  Phrenic  Nerve  (Nervus  Phrenicus,  Diaphragmaticus) 
arises,  in  the  manner  seated  above,  from  the  anterior  fasciculus 
of  the  second  and  of  the  third  cervical,  and  is  assisted  generally 
by  two  or  three  filaments  from  the  upper  part  of  the  brachial 


492  NERVOUS  SYSTEM. 

plexus.  It  descends,  vertically,  on  the  humeral  side  of  the  in- 
ternal jugular  vein,  but  removed  a  considerable  distance  from  itr 
and  is  attached,  by  cellular  substance,  to  the  front  of  the  scale- 
nus  anticus  muscle.  Getting,  in  its  descent,  to  the  internal  mar- 
gin of  the  latter,  it  passes  into  the  thorax,  at  the  inner  margin 
of  the  first  rib,  between  the  subclavian  artery  and  the  subclavian 
vein,  the  latter  being  before  it.  It  then  goes  along  the  superior 
mediastinum  to  the  pericardium,  to  the  side  of  which  it  adheres 
in  front  of  the  root  of  the  lung,  being  between  the  pericardium 
and  the  corresponding  portion  of  the  pleura;  it  finally  reaches 
the  diaphragm,  to  which  it  is  distributed. 

Just  before  the  phrenic  nerve  reaches  the  diaphragm,  it  radi- 
ates into  several  branches,  which  interchange  filaments.  Some 
of  the  branches  are  distributed  to  the  convex  surface  of  the  dia- 
phragm; others  penetrate  the  muscle,  and  are  distributed  in  its 
thickness  and  upon  its  concave  surface.  On  the  right  side  some 
of  these  branches  pass  through  the  opening  for  the  ascending 
vena  cava,  and,  thus  getting  into  the  abdomen,  anastomose  with 
the  solar  plexus,  and  with  the  pneumogastric  nerve. 

The  phrenic  nerve  of  the  left  side  is  nearer  to  the  root  of  the 
lung  than  that  of  the  right,  in  consequence  of  the  projection  of 
the  apex  of  the  heart  on  that  side.  Its  distribution  in  other  re- 
spects does  not  present  any  remarkable  difference  from  the  other; 
its  branches  radiate  in  the  same  way  to  the  diaphragm,  and  sup- 
ply its  thickness,  as  well  as  its  upper  and  under  surfaces.  It 
sends  some  filaments  to  the  lower  part  of  the  oesophagus. 

The  phrenic  gives  off  in  the  neck  a  few  filaments  to  the  sca- 
lenus  anticus,  and  the  rectus  anticus  major  muscle.  It  also  com- 
municates there,  with  filaments  from  the  inferior  cervical  gang- 
lion, and  sometines  from  the  superior  cervical. 


Of  the  Four  Inferior  Cervical  Nerves. 

The  trunks  of  these  nerves,  on  issuing  from  the  intervertebral 
foramina,  have  one  general  mode  of  distribution,  which  permits 
them  to  be  described  together  or  in  common. 

The  posterior  branches  are  much  smaller  than  those  of  the 
preceding  cervical  nerves;  they  go  backwards  between  the 


UPPER  AND  LOWER  SPINAL  NERVE.  493 

complexus  and  the  transversalis  colli,  and  leave  filaments  in 
their  passage  with 'them;  they  then  reach  the  splenius  and  the 
trapezius,  to  which  and  to  the  integuments  of  the  neck  they  are 
distributed. 

The  anterior  branches  are  large ;  they  appear  on  the  side  of 
the  neck,  between  the  scalenus  antic  us  and  medius  muscle;  some- 
times perforating  the  substance  of  one  or  the  other  of  these  mus- 
cles. They  each  detach  filaments  to  the  sympathetic.  The 
fourth,  also,  commonly  sends  one  to  the  phrenic.  They  then 
form  the  Brachial  Plexus, 


Of  the  Brachial  Plexus  and  the  Nerves  of  the  Upper  Extremity. . 

The  Brachial  or  the  Axillary  Plexus  is  formed  by  the  junction 
and  the  intertexture  of  the  four  inferior  cervical  nerves,  and  the 
first  dorsal  or  thoracic.  It  extends  from  the  scaleni  muscles  to 
the  axilla,  on  a  level  with  the  neck  of  the  os  humeri.  The  nerves 
at  first  converge,  and  are  situated  somewhat  behind  the  subcla- 
vian  artery  where  it  passes  over  the  first  rib ;  but  are  at  various 
heights  above  it,  according  to  their  origin,  with  the  exception  of 
the  first  dorsal  nerve,  which  has  to  ascend  in  order  to  pass  out 
of  the  thorax. 

The  plexus  is  formed  in  the  following  manner.  The  fourth 
and  the  fifth  cervical  nerves  unite  near  the  scaleni  muscles  into 
a  single  trunk,  which  runs  a  short  distance  downwards,  and 
then  splits  into  two.  The  seventh  cervical  and  the  first  dorsal 
do  the  same.  The  sixth  cervical  is  the  central  nerve  of  the 
plexus,  and  after  going  downwards  two  or  three  inches,  it  bi- 
furcates also.  Combinations  of  these  primary  divisions  are  formed, 
which  are  dissolved,  and  then  reformed,  in  such  a  way  that  a 
thorough  intertexture  of  the  original  nerves  takes  place.  This 
intertexture  surrounds  the  axillary  artery  somewhat  like  the 
braids  of  a  whip-cord,  from  the  clavicle  to  the  os  humeri  below 
its  head.  In  this  course  the  axillary  plexus  passes  along  with 
the  artery  between  the  subclavius  muscle  and  the  first  rib,  lies 
in  contact  with  the  superior  part  of  the  serratus  major  anticus 
muscle,  and  immediately  below  the  articulation  of  the  shoulder 
joint.  The  axillary  vein  is  in  front  of  it. 

VOL.  II.— 63 


494  NERVOUS  SYSTEM. 

The  nerves  which  proceed  from  the  axillary  plexus  are  the 
Scapular ;  the  Thoracic ;  the  Axillary;  the  two  Cutaneous ;  the 
Radial ;  the  Ulnar ;  and  the  Median.  They  supply  the  superior 
extremity,  including  the  shoulder  and  the  axilla. 

1.  The  Nervus  Scapularis  is  a  small  branch  coming  common- 
ly from  the  upper  part  of  the  plexus,  as  formed  by  the  fourth 
cervical  nerve.     It  goes  backwards  in  company  with  the  arte- 
ria  dorsalis  superior  scapulae,  through  the  notch  or  foramen  of 
the  upper  costa  of  the  scapula;  and  having  thus  got  to  the  pos- 
terior face  of  the  latter,  it  gives  filaments  to  the  supra  spinatus 
muscle ;  continuing  its  course  then  on  the  posterior  face  of  the 
cervix  scapulae,  it  is  lost  in  filaments  upon  the  infra-spinatus  and 
teres  minor  muscles. 

2.  The  Newi  Subscapulares  of  Bichat  present  some  varieties 
in  their  origin ;  occasionally  they  come  from  the  same  trunk,  but 
commonly  each  one  has  its  peculiar  root  from  the  central  parts 
of  the  axillary  plexus.     They  are  generally  three  of  them.    One 
of  them  descends  behind  the  axillary  vessels,  between  the  sub- 
scapularis  and  the  serratus  major  anticus ;  it  crosses  the  teres 
major,  and  is  lost  upon  the  contiguous  part  of  the  latissimus  dor- 
si.     Another  is  distributed  upon  the  subscapularis  muscle.     The 
third  descends  along  the  anterior  margin  of  the  subscapularis  for 
a  short  distance,  and  distributes  filaments  to  it,  to  the  teres  mi- 
nor and  major  muscles. 

3.  The  Nervi  Thoracici  are  primarily  two  or  three  in  number, 
and  proceed  from  about  the  middle  of  the  plexus.     The  fascicu- 
li into  which  they  are  resolved,  may  be  distinguished  as  anterior 
and  posterior.     The  former  are  distributed,  by  filaments,  to  the 
subclavian  muscle,  to  the  pectoralis  minor  and  major,  and  to  thie 
integuments  covering  the  latter.     The  posterior  thoracic  has  its 
origin  somewhat  concealed  by  the  scalejius  anticus  muscle.     It 
descends  into  the  axilla,  adhering  to  the  serratus  major  muscle 
for  some  distance,  and  is  then  distributed  by  many  filaments  to 
this  muscle. 

4.  The  Nervus  Axillaris,  or  Circwnflextts,  comes  from  the  infe- 


UPPER  NINE  SPINAL  NERVES.  495 

rior  part  of  the  plexus.  Immediately  after  its  origin,  it  goes 
downwards  and  outwards  over  the  upper  extremity  of  the  sub- 
scapularis  muscle.  It  then  winds  around  the  os  humeri,  between 
the  teres  minor  and  major  muscles,  observing  the  course  of  the 
posterior  circumflex  artery,  and,  finally,  terminates  on  the  under 
surface  of  the  deltoid  muscle. 

This  nerve  sometimes  gives  off  the  subscapular,  and,  indeed, 
it  is  usual  for  anatomists  to  include  the  description  of  the  latter 
in  it.  As  it  turns  around  the  bone,  it  divides  into  two  principal 
trunks ;  the  superior  goes  to  the  inferior  margin  of  the  infra-spi- 
natus,  and  to  the  posterior  margin  of  the  deltoides ;  the  inferior 
is  distributed  principally  in  the  substance  of  the  deltoid  muscle, 
but  some  of  its  filaments,  by  perforating  the  latter,  reach  the  skin, 
and  constitute  the  nervus  cutaneus  humeri.  Filaments  go  from 
the  nervus  axillaris,  in  the  early  part  of  its  course,  to  the  subsca- 
pularis  and  the  two  teres  muscles. 

5.  The  Nervus  Cutaneus  Internus*  arises  from  the  lower  part 
of  the  axillary  plexus,  and  is  one  of  the  smallest  of  those  which 
go  to  the  arm.  It  is  situated  between  the  median  and  the  ulnar 
nerve,  and  adheres  almost  as  far  as  the  elbow,  to  the  basilic 
vein.  In  its  descent,  this  nerve  detaches  several  small  filaments, 
which,  perforating  the  fascia  of  the  arm,  are  distributed  to  the 
integuments  of  the  biceps  muscle,  and  to  those  on  the  internal 
face  of  the  triceps. 

Somewhat  above  the  bend  of  the  elbow,  at  the  place  where 
the  median  basilic  vein  joins  the  basilic,  but  occasionally  some 
inches  higher  up,  the  internal  cutaneous  becomes  superficial,  and 
splits  into  two  branches  of  nearly  equal  magnitude,  which  di- 
verge but  little  from  each  other  at  first.  The  branch  nearest  the 
internal  condyle  of  the  os  humeri,  lies  in  front  of  the  basilic  vein, 
as  it  passes  over  the  elbow  joint ;  and  continues  in  this  position 
for  two  or  three  inches :  it  goes  down  the  front  of  the  fore  arm 
on  its  ulnar  side,  but  inclines  continually  to  the  back  of  the  fore 
arm.  In  this  course,  it  detaches  small  ramifications  to  the  inte- 
guments about  the  internal  condyle,  and  about  the  heads  of  the 
flexor  muscles ;  it  also  detaches  continually,  from  its  sides,  small 

*  Antonius  and  Caldani,  Tabul.  CCLVIII. 


496  NERVOUS  SYSTEM. 

filaments  to  the  integuments  of  the  ulnar  side  of  the  fore  arm 
both  anteriorly  and  posteriorly,  some  of  which  reach  to  the  hand. 
The  other,  or  the  external  branch  of  the  internal  cutaneous, 
•which  is  nearer  the  radius,  passes  beneath  the  median  basilic 
vein,  about  six  lines  from  the  basilic ;  but,  just  before  it  does  so, 
it  detaches  a  very  superficial  cutaneous  filament,  which  crosses 
in  front  of  the  median  basilic  vein  about  its  middle,  and  is  lost  a 
little  below  the  bend  of  the  arm.  The  outer  branch  of  the  in- 
ternal cutaneous  having  got  from  beneath  the  median  basilic 
vein,  goes  superficially  as  far  as  the  middle  of  the  fore  arm 
without  sending  off  any  filaments  of  note ;  it  is  then  divided  suc- 
cessively into  several,  which  diverge  to  supply  the  skin  down  to 
the  wrist. 

6;  The  Ne-rdus  Musculo*Culaneous,  or  Cutaneous  Externus,  is 
somewhat  larger  than  the  preceding,  and  arises  from  about  the 
middle  of  the  brachial  plexus.  It  descends  a  short  distance,  and 
then  perforates  obliquely  the  upper  part  of  the  coraco-brachialis 
muscle.  Having  passed  through  this  muscle,  it  continues  its 
course  obliquely,  between  the  brachialic  internus  and  the  bi- 
ceps flexor,  and,  finally,  makes  its  appearance  superficially  on 
the  outer  side  of  the  tendon  of  the  latter.  In  this  course,  it 
distributes  filaments  to  the  several  muscles  with  which  it  is  con- 
nected. 

It  afterwards  passes  the  elbow  joint  under  the  median  cepha- 
lic vein  near  its  middle,  and  descends  between  the  skin  and 
the  fascia  of  the  fore  arm,  near  the  outer  margin  of  the  me* 
dian  vein,  to  the  hand :  in  this  course,  it  is  parallel  with  and 
on  the  front  of  the  supinator  radii  longus.  It  distributes  many 
filaments  to  the  corresponding  integuments  on  the  radial  side  of 
the  fore  arm,  and,  having  at  length  got  near  the  lower  end  of 
the  radius,  it  divides  into  two  orders  of  fibres,  one  of  which 
is  distributed  to  the  integuments  on  the  dorsal,  and  the  other 
to  those  on  the  palmar  side  of  the  hand,  about  the  root  of  the 
thumb. 

7.  The  Nervits  Radinlis,  or  Muscuto  Spiralis,  arises  from 
the  upper  portion  of  the  brachial  plexus,  but  in  such  a  way, 
that  filaments  from  almost  every  part  of  the  latter  run  into  it. 


NERVES  OF  THE  UPPER  EXTREMITY.          497 

It  is  a  large  trunk  which  winds  spirally  around  the  os  humeri, 
between  the  triceps  muscle  and  the  bone,  entering  the  fissure 
between  the  first  and  the  third  head  of  the  triceps.  It  appears 
on  the  outside  of  the  03  humeri,  between  the  brachialis  internus 
and  the  triceps  muscle;  running  for  some  inches  in  contact  with 
their  intermuscular  ligament.  While  beneath  the  triceps,  it 
sends  several  branches  to  its  heads.  There  are  three  principal 
trunks  afterwards  from  this  nerve. 

a.  The  Ramus  Superficialis  Dorsalis  is  sent  from  it  on  a  line 
with  the  point  of  the  deltoid  muscle.  This  branch  then  goes 
just  below  the  skin,  parallel  with  and  over  the  external  ridge 
of  the  os  humeri;  it,  of  course,  crosses  the  origin  of  the  mus- 
cles of  the  external  condyle.  Jt  continues  superficial  on  the 
posterior  external  edge  of  the  supinator  radii  longus  muscle, 
and  terminates  in  the  integuments  on  the  back  of  the  hand. 

The  continued  trunk  of  the  muscular  spiral  goes  in  the  inter- 
stice between  the  extensor  muscles  and  the  brachialis  inter- 
nus, and,  at  the  external  condyle,  divides  into  the  other  two 
branches,  from  which  filaments  proceed  to  the  contiguous  heads 
of  the  muscles. 

b.  The  Ramus  Profundus  Dorsalis  perforates  the  supinator 
brevis  muscle,  getting  beneath  the  radial  extensors  to  the  back 
of  the  fore-arm;  it  is  then  distributed  in  numerous  filaments  to 
the  muscles  on  the  back  of  the  fore  arm,  some  of  its  branches 
reaching  to  the  wrist. 

c.  The  Ramus  Superficialis  Anterior  seems  to  be  a  continua- 
tion of  the  main  trunk  of  the  nerve,  and  descending  at  the  an- 
terior margin  of  the  supinator  radii  longus  muscle,  it  joins 
with  the  radial  artery  and  continues  in  its  company  to  a  short 
distance  below  the  middle  of  the  radius.     Here  it  crosses  the 
bone  obliquely  beneath  the  tendon  of  the  supinator  longus, 
and  then  divides  into  a   palmar  and   a  dorsal   ramuscle;    the 
first  being  distributed  to  the  muscles  and  integuments  of  the 
thumb,  the  second    terminating  so  as  to  supply  the  back  of 
the  hand,  of  the  thumb,  fore,  middle,  and  ring  fingers  to  their 
extremities.  , 

8.   The  Nervus  Medianus  descends  the  arm  at  the  inner 
edge  of  the  biceps  muscle;  along  the  anterior  surface  of  the 


498  NERVOUS  SYSTEM. 

brachial  artery,  adhering  firmly  to  it,  and  the  deep-seated  veins, 
by  cellular  substance.  As  far  as  the  elbow,  it  sends  off  no 
branch  of  importance.  There  it  lies  at  the  side  of  the  biceps 
tendon,  crosses  the  lower  part  of  the  brachialis  internus,  and  is 
beneath  the  aponeurosis  of  the  biceps.  It  then  perforates  the 
pronator  teres  and  gets  between  the  flexor  sublimis  digito- 
rum,  and  the  flexor  longus  pollicis,  and  enters  the  palm  of 
the  hand  under  the  ligament  of  the  wrist,  at  the  radial  edge 
of  the  tendons  of  the  flexor  sublimis.  In  the  palm  it  is  situ- 
ated beneath  the  aponeourosis  pulmaris  and  the  arcus  sublimis 
of  the  arteries. 

The  median  nerve  dispenses  the  following  branches: — At 
the  bend  of  the  arm,  it  furnishes  filaments  to  the  heads  of  the 
first  layer  of  muscles  of  the  fore  arm;  and  a  little  below,  it  de- 
taches the  nervus  interosseous,  which  supplies  filaments  to  the 
flexor  longus  pollicis  and  flexor  profundus  digitorum.  The  in- 
terosseous nerve  then  descends  with  the  interosseous  artery  in 
front  of  the  interosseous  ligament,  and  terminates  in  the  prona- 
tor quadratus. 

Before  the  median  nerve  reaches  the  wrist,  it  sends  a  branch 
which  supplies  with  filaments  the  muscles  and  integuments  of 
the  ball  of  the  thumb.  In  the  palm  of  the  hand,  it  divides  and 
subdivides  so  as  to  send  a  branch  to  each  side  of  the  thumb,  of 
the  fore,  and  of  the  middle  finger,  and  to  one  side  of  the  ring 
finger.  These  branches  go  along  with  the  arteries  to  the  ends 
of  the  fingers  and  thumb. 

9.  The  Nervus  Ulnaris  comes  from  the  lowest  section  of 
the  brachial  plexus.  It  descends  along  the  internal  anterior 
part  of  the  triceps  muscle,  in  a  groove  formed  between  it,  and 
the  intermuscular  ligament;  it  diverges,  in  this  course,  gradu- 
ally from  the  median  nerve  till  it  reaches  the  elbow,  when  it  is 
at  its  greatest  point  of  separation.  At  the  elbow,  it  is  behind 
the  internal  condyle,  in  the  groove  between  it  and  the  olecra- 
non,  and  separates  the  two  heads  of  the  flexor  ulnaris  mus- 
cle. It  then  gets  to  the  fore  arm  between  this  muscle  and 
the  flexor  profundus  digitorum,  and  continues  between  them 
to  within  two  inches  of  the  wrist  joint,  when  it  detaches  the 
Ramus  Dorsalis. 


NERVES  OP  THE  UPPER  EXTREMITY.  499 

The  Ramus  Dorsalis  dips  between  the  ulna  and  the  tendon 
of  the  flexor  ulnaris,  runs  along  the  internal  margin  of  the  ulna 
to  the  carpus;  it  then  divides  into  ramuscles,  which  supply  the 
ulriar  side  of  the  integuments  on  the  back  of  the  hand,  and  on 
the  backs  of  the  two  last  fingers.  At  the  interval  behind,  be- 
tween the  heads  of  the  metacarpal  bones  of  the  middle  and 
ring  fingers,  a  considerable  ramuscle  joins  one  from  the  branch 
of  the  muscular  spiral  nerve  which  attended  the  radial  ar- 
tery. 

The  Ulnar  Nerve,  having  given  off  this  dorsal  branch,  de- 
scends along  the  radial  margin  of  the  tendon  of  the  flexor  ul- 
naris and  the  os  pisiforme,  above  the  annular  ligament,  to  the 
palm  of  the  hand.  Getting  beneath  the  aponeurosis,  it  there 
detaches  first  a  deep-seated  branch,  which  penetrates  the  mus- 
cles of  the  little  finger  to  supply  them,  the  interossei,  and  the 
short  flexor  of  the  thumb.  The  ulnar  nerve  then  furnishes  a 
superficial  branch,  and  afterwards  divides  into  three;  one  for 
the  ulnar  side  of  the  little  finger,  another  for  the  opposing  sides 
of  the  little  and  ring  finger,  and  a  third  which  joins  the  most 
internal  digital  branch  of  the  median  nerve. 


SECT.  II. OP  THE  THORACIC  SPINAL  NERVES. 

The  Dorsal  or  Thoracic  Spinal  Nerves  (Nervi  Thoracici, 
Dorsales)  consist  in  twelve  pairs,  the  first  pair  goes  through 
the  intervertebral  foramina,  between  the 'first  and  the  second 
dorsal  vertebra,  and  the  twelfth  pair  between  the  last  dor- 
sal and  the  first  lumbar  vertebra.  The  common  trunk,  formed 
after  the  ganglion  of  each  nerve,  goes  but  a  short  distance  when 
it  divides  into  an  anterior  and  a  posterior  branch. 

The  Posterior  Branch  (Ramus  Dorsalis)  of  each  nerve, 
goes  backwards  between  the  transverse  process  of  the  corre- 
sponding vertebrae,  and,  having  got  beneath  the  multifidus  spinaer 
is  commonly  subdivided  into  internal  and  external  ramuscles. 
The  internal  are  the  smaller,  and  are  distributed  upon  the  mus- 
cles lying  upon  the  spine,  as  the  multifidus,  the  sacro-lumbalis, 


500  NERVOUS  SYSTEM. 

longissimus  dorsi,  and  so  on:  their  terminating  filaments  reach 
the  skin.  The  external  branches  descend  obliquely  outwards 
beneath  the  longissimus  dorsi,  and  then  issue  between  the  latter 
and  the  sacro-lumbalis,  to  both  of  which  they  dispense  filaments: 
they  afterwards  are  divided  into  branches,  which  go  to  the  tra- 
pezius,  latissimus  dorsi,  rhomboideus  and  to  the  corresponding 
integuments. 

The  Anterior  Branches  of  the  Dorsal  Nerves  (Kami  Sub- 
costales)  correspond  with  the  intercostal  spaces  of  the  ribs. 
Each  one,  in  a  short  course  after  its  origin,  applies  itself  to  the 
rib  just  above  it,  and  accompanies  the  intercostal  vessels  in  the 
groove,  formed  in  the  under  margin  of  each  rib.  After  it  pro- 
ceeds about  two-thirds  of  the  length  of  the  rib,  it  separates  gra- 
dually from  it,  and  goes  nearer  the  middle  of  the  intercostal 
space  and  the  superior  margin  of  the  rib  below.  To  the  angle 
of  the  rib,  each  nerve  is  only  covered  in  front  by  the  pleura, 
but  afterwards  it  goes  between  the  intercostal  muscles.  Near 
the  sternum,  the  branches  become  superficial  by  escaping  from 
between  the  intercostal  muscles,  and  are  distributed  upon  the 
pectoral  muscles,  and  the  adjacent  skin.  These  terminating 
branches  of  the  five  or  six  inferior  dorsal  nerves  go  to  the  upper 
portions  of  the  abdominal  muscles  and  their  integuments.  Not 
far  from  its  origin,  each  dorsal  nerve  anastomoses  with  the  gang- 
lion or  chord  of  the  sympathetic,  after  the  manner  described  in 
the  account  of  the  latter  nerve. 

There  are  some  differences  between  the  thoracic  nerves  in 
their  manner  of  distribution. 

The  anterior  fasciculus  of  the  first,  as  mentioned,  forms  the 
lower  part  of  the  axillary  plexus  ny  joining  itself  to  the  se- 
venth cervical.  It  sends  out,  however,  a  subcostal  branch 
which  goes  along  the  inferior  face  of  the  first  rib,  supplying'the 
intercostal  muscles  and  having  the  general  distribution  al- 
luded to. 

The  Second  Subcostal  Branch,  besides  the  common  distribu- 
tion, detaches  a  fasciculus,  which,  penetrating  between  the  ribs, 
gets  into  the  axilla  and  is  augmented  by  a  branch  from  the 


THORACIC  SPINAL  NERVES.  501 

internal  cutaneous  nerve  of  the  upper  extremity.  It  then  de- 
scends along  the  internal  posterior  face  of  the  arm  to  the  elbow, 
and  in  this  course  detaches  several  fine  filaments  to  the  integu- 
ments. 

The  Third  Subcostal  Branch  in  like  manner  detaches  an 
axillary  fasciculus  which  goes  to  the  inferior  part  of  the  arm- 
pit, to  the  integuments  of  which,  and  to  those  on  the  internal 
face  of  the  arm,  it  is  distributed.  It  does  not  descend  quite  so 
low  as  the  preceding.  These  two  nerves  are  called  Intercosto- 
Humeral,  and  from  their  origin  and  course,  are  supposed  to 
account  for  the  numbness  of  the  arm,  in  cases  of  angina  pec- 
toris. 

The  Fourth,  Fifth,  Sixth,  and  Seventh  Subcostal  Branches 
of  the  Dorsal  or  Thoracic  Nerves,  about  the  middle  of  the  ribs 
to  which  they  respectively  belong,  are  all  divided  into  two 
branches.  One  of  them,  which  is  properly  speaking  the  in- 
tercostal, continues  in  the  intercostal  space,  giving  filaments  to 
its  muscles  and  to  the  triangularis  sterni;  it  then  emerges  near 
the  sternum  to  terminate  upon  the  great  pectoral  muscle,  the 
mamma,  and  the  integuments  of  the  front  of  the  thorax.  The 
other  branch  is  the  external  pectoral:  it  extricates  itself  earlier 
from  the  intercostal  space,  and  is  distributed  upon  the  muscles 
and  the  integuments  on  the  side  of  the  thorax. 

The  remaining  subcostal  branches,  to  the  eleventh  inclu- 
sively, have  very  much  the  same  principle  of  distribution. 
Their  intercostal  fasciculi,  having  reached  the  anterior  ends 
of  the  intercostal  spaces,  pass  on  to  the  abdominal  parietes,  be- 
tween the  transversalis  muscle  and  the  internal  oblique,  to  both 
of  which  they  give  filaments.  They  reach  the  external  margin 
of  the  rectus  abdominis  muscle,  and  then  divide  into  filaments, 
some  of  which  go  to  this  muscle,  others  pierce  the  fore  part  of 
its  sheath  and  are  ramified  upon  the  integuments  of  the  front  of 
the  abdomen. 

The  Twelfth  Subcostal  Branch  of  the  Dorsal  Nerves,  sends 
first  a  branch  downwards,  which  joins  with  the  first  lumbar 
nerve.  It  then  crosses  in  front  of  the  quadratus  lumborum 
muscle,  to  which  it  gives  filaments  as  well  as  to  the  adjoining 
portion  of  the  diaphragm.  It  afterwards  divides  into  two 
branches,  the  superior  of  which  goes  for  some  distance  between 
VOL.  II.— 64 


502  NERVOUS  SYSTEM. 

the  two  oblique  muscles  of  the  abdomen,  detaching  filaments 
to  them,  and  finally  terminates  on  the  integuments  of  the  ab- 
domen; the  other  branch  goes  between  the  transversalis  and 
the  internal  oblique,  and  is  extended  to  the  lower  part  of  the 
rectus,  and  to  the  pyramidalis  muscle,  to  all  of  which  it  distri- 
butes filaments. 


SECT.  III. — OP  THE  ABDOMINAL  SPINAL  NERVES. 

There  are  five  lumbar,  and  five,  sometimes  six,  sacral  nerves 
on  each  side;  the  first  of  them  passes  out  of  the  intervertebral 
foramen,  between  the  first  and  the  second  lumbar  vertebra;  and 
the  remaining  lumbar  and  sacral  nerves  go,  successively,  through 
the  foramina  in  the  loins  and  in  the  sacrum. 

The  anterior  fasciculi  of  these  nerves,  form  a  plexus  which 
extends  from  the  upper  part  of  the  loins  to  the  lower  part  of 
the  sacrum;  it  is  designated  under  the  general  term  of  Plexus 
Cruralis.  The  posterior  fasciculi  are  much  smaller.  Those  of 
the  loins  go  backwards  between  the  transverse  processes,  and 
are  distributed  upon  the  sacro-lumbalis,  the  longissimus  dorsi,  the 
multifidus  spinse,  and  the  corresponding  integuments.  The  pos- 
terior fasciculi  of  the  sacral  nerves  are  not  so  large,  generally, 
as  those  of  the  lumbar:  they  get  out  through  the  foramina,  on 
the  posterior  face  of  the  sacrum,  are  distributed  to  the  same 
muscles;  to  the  origin  of  the  glutaeus  magnus,  and  to  the  inte- 
guments of  the  sacrum,  and  of  the  adjoining  portion  of  the  but- 
tocks. 

The  Plexus  Cruralis,  for  the  purpose  of  description,  has  been 
divided  by  anatomists  into  the  Plexus  Lumbalis,  formed  by  the 
four  superior  lumbar  nerves,  and  the  Plexus  Ischiadicus,  formed 
by  the  last  lumbar  and  the  sacral  nerves. 

The  Lumbar  Plexus  (Plexus  Lumbalis}  is  concealed  by  the 
psoas  magnus  muscle,  and  is  placed  between  it,  the  lumbar  ver- 
tebrae, and  the  quadratus  lumborum:  frequently  the  roots  of  the 
nerves  forming  this  plexus  penetrate  through  the  substance  of 
the  psoas  magnus,  and  form  their  unions  in  it.  The  plexus  is 
narrow  and  pointed  above,  where  it  commences  by  the  fasci- 
culus of  the  last  dorsal  nerve  joining  the  first  lumbar;  but  it  in- 


ABDOMINAL  SPINAL  NERVES.  503 

creases  continually  afterwards  in  breadth,  owing  to  the  nerves 
composing  it,  successively  anastomosing  farther  and  farther  from 
the  spinal  column.  From  this  plexus  proceed  three  principal 
trunks:  the  upper  one  (Cruralis  interior)  is  of  considerable 
size;  and  goes  to  the  skin  and  the  muscles  on  the  front  of  the 
lower  extremity;  the  middle  (Nervus  Obturator)  is  not  so 
large  as  the  preceding,  and  goes  through  the  obturator  foramen 
to  the  adductor  muscles  of  the  thigh;  the  inferior,  formed  by  the 
whole  of  the  fifth  and  a  fasciculus  from  the  fourth  lumbar  nerve, 
joins  the  upper  part  of  the  sciatic  plexus  in  the  pelvis.  Besides 
these,  there  are  several  branches  of  smaller  size  and  of  less  im- 
portance, proceeding  from  the  lumbar  plexus. 

The  Mdomino  Crural  Branches,  according  to  Bichat,  are 
most  commonly  three  in  number,  and  come  from  the  two  upper 
lumbar  nerves.  The  first  of  them  goes  obliquely  downwards  and 
outwards,  in  front  of  the  quadratus  lumborum,  to  the  posterior 
part  of  the  spine  of  the  ilium,  and  runs  for  a  short  distance  along 
the  crista  of  the  bone:  it  gives  filaments  to  the  iliacus  internus, 
and  to  the  abdominal  muscles,  where  they  border  on  this  part 
of  the  bone.  Some  of  the  filaments  become  cutaneous,  but  the 
main  trunk  of  the  nerve  reaches  the  anterior  superior  spinous 
process,  by  going  between  the  transversalis  and  the  internal  ob- 
lique muscle;  it  then  follows  the  inguinal  arch  to  the  external  ring, 
through  which  it  passes,  and  is  distributed  in  filaments  upon  the 
groin,  the  pubes,  and  the  scrotum.  The  second  or  middle  branch 
arises  from  the  plexus  near  the  preceding;  it  descends  along  the 
external  margin  of  the  psoas  magnus,  and  crosses  the  ilia- 
cus internus,  covered  by  the  peritoneum;  near  the  anterior 
superior  spinous  process,  it  gets  between  the  lower  margins 
of  the  abdominal  muscles,  and  is  distributed  upon  them  there: 
some  of  its  ramifications  get  also  through  the  external  ring,  and 
may  be  traced  to  the  scrotum.  The  third,  or  the  inferior  branch, 
arises  from  the  plexus  still  lower  down,  and,  after  having  tra- 
versed the  front  of  the  iliacus  internus,  it  emerges  from  the  pel- 
vis beneath  Poupart's  ligament,  near  the  anterior  superior  spi- 
nous process;  it  then  divides  into  filaments  which  penetrate  to 
the  skin  through  the  femoral  fascia,  and  are  distributed  along 
the  external  anterior  face  of  the  thigh. 


504  NERVOUS  SYSTEM. 

The  Spermaticns  Externus  arises  from  the  upper  part  of 
the  plexus,  by  a  fasciculus  from  the  first  lumbar  nerve,  which 
is  increased  by  one  from  the  second  lumbar.  It  descends  at 
first  in  the  body  of  the  psoas  magnus  muscle  and  then  in  front 
of  it:  it  crosses  the  iliacus  internus,  somewhat  above  Poupart's 
Ligament,  by  directing  its  course  towards  the  anterior  superior 
spinous  process  of  the  ilium.  Here,  it  involves  itself  in  the 
edge  of  the  abdominal  muscles,  and  goes  on  the  posterior  face 
of  Poupart's  ligament;  at  the  internal  abdominal  ring  it  joins 
the  spermatic  chord  of  the  male,  or  the  round  ligament  of  the 
uterus  of  the  female.  In  the  first  case,  it  is  distributed  to  the 
spermatic  chord  and  scrotum;  in  the  second,  to  the  labium  ex- 
ternum  and  mons  veneris. 

The  Cutaneus  Externus  arises  from  the  lumbar  plexus  be- 
low the  external  spermatic.  It  passes  across  the  iliacus  in- 
ternus towards  the  anterior  superior  spinous  process,  about  an 
inch  below1  the  spermaticus  externus,  and  crosses  the  latter 
nerve  just  at  that  process.  Emerging  from  the  abdomen,  by 
penetrating  the  commencement  of  Poupart's  ligament,  it  is  dis^ 
tributed  in  several  branches  to  the  integuments  of  the  vastus 
externus  muscle,  and  along  the  edge  of  the  rectus  femoris:  one 
of  the  latter  extends  to  the  patella. 

The  Cutaneus  Medius  is  detached  from  the  anterior  crural, 
an  inch  or  so  above  Poupart's  ligament.  It  arises  among  the 
cluster  of  branches,  which  come  off  there  to  be  distributed  to 
the  iliacus  internus  muscle,  and  to  the  muscles  of  the  thigh.  It 
appears,  superficially,  on  the  thigh,  for  the  first  time,  by  pene- 
trating the  sartorius  muscle,  about  the  internal  edge  of  the  rec- 
tus femoris:  it  descends  then  along  the  same  edge  of  the  latter 
muscle,  and  is  distributed  to  its  integuments.  It  does  not  de- 
scend so  low  as  the  external  cutaneous. 

The  Cutaneus  interior  arises,  also,  from  the  crural  nerve. 
It  is  on  the  inner  side  of  the  cutaneus  medius,  emerges  from  the 
fascia  of  the  thigh,  and  crosses  the  sartorius  muscle  two  or  three 
inches  below  the  cutaneus  medius.  It  is  distributed  on  the  in- 
teguments of  the  vastus  internus  muscle,  and  some  of  its  branches 
extend  to  the  internal  edge  of  the  patella. 


ABDOMINAL  SPINAL  NERVES.  505 

The  Cutaneus  Infernus  arises  from  the  anterior  crural  nerve, 
among  the  same  cluster,  above  Poupart's  ligament.  It  divides 
into  four  or  five  branches  of  different  lengths,  and  is  distributed 
to  the  integuments  of  the  adductor  muscles,  and  along  the  inner 
front  side  of  the  thigh.  One  branch  observes  very  much  the 
course  of  the  tendon  of  the  adductor  magnus,  and  reaches  as  far 
down  as  the  inner  side  of  the  knee. 

The  Cruralis  interior  arises  from  the  middle  of  the  lum- 
bar plexus;  at  first,  it  is  beneath  the  psoas  magnus  muscle;  it 
then  gets  to  its  outside,  and  passes  from  the  abdomen,  under 
Poupart's  ligament,  about  half  an  inch  from  the  outside  of  the 
femoral  artery.  Before  it  reaches  Poupart's  ligament,  it  gives 
off  a  cluster  of  nerves,  several  of  which  go  to  the  iliacus  inter* 
mis  muscle;  others  form  the  superficial  or  cutaneous  nerves  of 
the  thigh  just  mentioned;  and  others,  the  deep-seated  or  mus- 
cular branches,  which  supply  the  adductor  muscles,  the  four 
extensors,  the  pectineus,  the  sartorius,  and  the  gracilis. 

One  of  the  branches  of  the  anterior  crural  nerve  is  seen  to 
accompany  the  femoral  artery,  till  the  artery  penetrates  the 
adductor  magnus;  it  then  runs  along  the  front  margin  of  the 
tendon  of  the  adductors  in  a  theca  formed  by  this  tendon  and 
the  origin  of  the  vastus  internus.  The  nerve  alluded  to  is  the 
Saphenus;  it  passes  afterwards  between  the  internal  condyle 
of  the  os  femoris  and  the  sartorius  muscle,  attaches  itself  to 
the  saphena  vein,  and  is  distributed  to  the  integuments  of  the 
inner  side  of  the  leg,  and  of  the  upper  internal  parts  of  the 
foot. 

The  Nervus  Obturatorius  is  derived  from  the  middle  of  the 
lumbar  plexus,  also;  and  has  very  much  "the  same  position,  in 
regard  to  the  psoas  magnus,  as  the  anterior  crural  nerve.  It 
descends  into  the  pelvis  from  beneath  the  psoas  magnus,  near 
the  sacro-iliac  articulation;  and  passes  forwards  and  downwards 
to  the  obturator  foramen;  having  got  through  which  it  divides 
into  an  anterior  and  posterior  branch.  The  first  is  distributed 
to  the  head  of  the  adductor  longus  and  brevis,  and  to  the  gra- 
cilis and  integuments.  The  second  terminates  in  the  obturator 
externus,  and  the  adductor  magnus. 


506  NERVOUS  SYSTEM. 

The  Sciatic  Plexus  (Plexus  Isthiadicus)  is  formed  by  the 
union  of  the  last  lumbar  with  the  four  upper  sacral  nerves; 
the  last  lumbar,  before  it  joins  the  plexus^  receiving  the  branch 
of  the  fourth  lumbar  nerve,  which  is  left  after  the  lumbar  plex- 
us is  formed.  This  plexus  is  situated  at  the  side  of  the  rectum 
before  the  pyriformis  muscle. 

The  volume  of  the  posterior  branches  of  the  Sacral  Nerves 
increases  till  the  fourth;  but  the  fifth  and  the  sixth  are  much 
smaller,  in  fact  only  fibrillae. 

The  anterior  branches  of  the  sacral  nerves  are  much  larger 
than  the  posterior.  The  four  first  communicate  with  the  sacral 
ganglions  of  the  great  sympathetic,  besides  forming  the  ischi- 
atic  plexus.  The  third  and  the  fourth,  assisted  by  the  sympa- 
thetic, form  the  hypogastric  plexus.  The  fifth,  and  the  sixth, 
when  it  exists,  are  distributed  to  the  coccygeus,  sphincter,  and 
levator  ani.* 

The  following  small  branches  go  from  the  Sciatic  Plexus.f 

a.  Nervi  Glutsei:  one  passes  through  the  upper  part  of  the 
sciatic  notch  along  with  the  artery,  to  the  glutseus  medius  and 
minimus;  another  below  the  pyriformis  muscle  to  the  glutseus 
magnus. 

b.  Nervus  Pudendalis  Longus  Inferior,  passes  under  the 
tuber  of  the  ischium  to  the  glutaeus  magnus;   perineal   mus- 
cles;   urethra  and    integuments  of  the  penis  and    scrotum  in 
men;  and   to  the  inferior  parts  of  the  labium  externum  in  wo- 
men. 

c.  Ramus  Femoralis  Cutaneus  Posterior.     This  nerve  is 
placed  between  the  integuments  of  the  thigh  and  the  muscles 
which  arise  from  the  tuberosity  of  the  ischium.     It  sends  many 
branches,  successively,  to  the  skin  on  the  back  of  the  thigh;  one 
of  its  branches,  longer  than  the  others,  goes  down  to  the  ham, 

•  This  is  only  given  as  the  most  frequent  arrangement  of  the  sciatic  plexus, 
and  of  the  branches  of  nerves  which  proceed  from  it;  other  arrangements  will 
often  be  met  with  in  the  cavity  of  the  pelvis,  in  which  not  so  many  sacral  nerves 
are  sent  to  the  plexus  ischiadicus,  and  the  several  branches  proceeding  from  it, 
depart  in  a  different  manner. 

f  They  sometimes  come  from  a  common  trunk  called,  in  such  case,  the  Small 
Sciatic. 


ABDOMINAL  SPINAL  NERVES.  507 

and  there  divides  in|to  several  filaments,  which  are  distributed  to 
the  integuments  on  the  back  of  the  leg. 

The  Nervus  Pudendalis  Longus  Superior  comes  from  the 
third  and  fourth  sacral.  It  goes  in  company  with  the  internal 
pudic  artery  between  the  sacro-sciatic  ligaments,  and  then  di- 
vides into  two  branches;  the  inferior  is  distributed  to  the  in- 
teguments and  muscles  of  the  perineum,  to  the  urethra  and 
scrotum;  the  superior  passing  along  the  ramus  of  the  ischmm 
and  pubes  with  the  trunk  of  the  internal  pudic  artery,  is  dis- 
tributed to  the  obturator  internus,  accelerator  urinse,  urethra, 
and  afterwards,  getting  between  the  symphysis  of  the  pubes 
and  the  penis,  terminates  on  its  integuments  and  the  glans 
penis. 

The  Nervus  Ischiadicus,  or  the  Great  Sciatic,  is  the  com- 
mon trunk,  formed  from  the  sciatic  plexus;  it  is  much  the 
largest  nerve  in  the  body,  and  passes  from  the  pelvis  between 
the  pyriformis  and  the  geminus  superior.  It  crosses,  vertical- 
ly, the  small  rotator  muscles  of  the  thigh,  being  concealed  by 
the  inferior  edge  of  the  glutaeus  magnus;  it  is  there  about  half- 
way between  the  tuberosity  of  the  ischium  and  the  trochanter 
major.  Thence  it  descends  on  the  back  of  the  adductor  mag- 
nus, at  the  outer  edge  of  the  long  head  of  the  biceps  flexor  cru- 
ris.  About  half  way  down  the  thigh,  sometimes  a  little  lower, 
the  Sciatic  Nerve  divides  into  the  Popliteal,  or  Posterior  Tibi- 
al,  and  Peroneal.  Occasionally  this  division  takes  place  as  high 
as  the  exit  of  the  nerve  from  the  pelvis;  but  in  this  case  the 
fasciculi  are  parallel  with  each  other  as  far  as  the  middle  of  the 
thigh.  From  the  trochanter  minor  to  its  usual  place  of  division, 
this  nerve  is  parallel  with,  and  on  the  back  of  the  thigh  bone; 
afterwards  the  two  branches  begin  to  diverge.  The  popliteal 
nerve  continues  straight  downwards  to  the  back  and  middle 
of  the  knee-joint,  and  to  the  interstice  between  the  heads  of  the 
gastrocnemius  muscle;  whereas  the  peroneal  nerve  goes  along 
the  inner  posterior  edge  of  the  biceps  flexor  cruris,  and  passes 
between  its  tendinous  insertion  and  the  external  head  of  the 
gastrocnemius  muscle. 

In  this  course,  the  following  branches  are  sent  from  the  scia* 


50S  NERVOUS  SYSTEM. 

tic.  —  Twigs  to  the  little  rotator  muscles  of  the  thigh.  —  The  Cu- 
taneus  Internus  Superior,  which  arises  near  the  upper  part  of 
the  thigh,  and  is  distributed  to  the  skin  of  the  corresponding 
part.  —  The  Cutaneus  Internus  Inferior,  which  arises  just  below 
the  last,  and,  descending  upon  the  inner  head  of  the  gastrocne- 
mius,  is  distributed  to  the  integuments  of  the  calf  of  the  leg.-— 
A  large  trunk,  and  sometimes,  instead  of  it,  distinct  branches, 
which  go  to  the  Adductor  Magnus,  Semi-membranosus,  Biceps, 
and  Semi-tendinosus. 

The  Peroneal  Nerve  (Nervus  Peroneus)  divides  at  the  head 
of  the  fibula  into  two  branches,  the  Peroneus  Externus  and 
the  Tibialis  Anterior;  but,  before  this  division,  it  sends  a  small 
branch  to  the  external  parts  of  the  knee-joint,  and  two  cutane- 
ous branches  called  Peroneo-Cutaneous.  The  Internal  Pero- 
neo-Cutaneous  descends  behind  the  external  head  of  the  gas- 
trocnemius,  and,  at  the  bottom  of  the  leg,  is  united  to  a  division 
of  the  posterior  tibial  called  the  External  Saphenus,  or  Commu- 
nicans  Tibiae.  The  External  Peroneo-Cutaneous  is  distributed 
to  the  skin,  along  the  fibula. 

The  External  Peroneal  Nerve  (Peroneus  Externus)  gets 
between  the  head  of  the  peroneus  longus  and  the  fibula,  then 
between  the  peroneus  longus  and  the  extensor  longus  digito- 
rum.  It  descends,  at  the  outer  edge  of  the  last  muscle,  to  the 
inferior  third  of  the  leg,  giving  out,  in  the  mean  time,  many 
muscular  branches.  Here  it  penetrates  the  aponeurosis,  and 
divides  into  cutaneous  branches,  which  supply  the  lower  part 
of  the  leg,  and  the  upper  surface  of  the  foot  and  toes.  This 
nerve  is  called,  by  the  French,  the  Musculo-Cutaneous  of  the 


The  Anterior  Tibial  Nerve  (Tibialis  interior)  gets  oblique- 
ly between  the  fibula,  the  peroneus  longus,  and  the  extensor 
longus  digitorum,  to  the  front  of  the  interosseous  ligament, 
where  it  accompanies  the  anterior  tibial  artery.  It  passes,  with 
the  artery,  under  the  annular  ligament  of  the  ankle,  and  has  its 
terminating  filaments  going  to  the  muscles  and  integuments  of 
the  upper  surface  of  the  foot,  as  far  as  the  end  of  the  two  first 


ABDOMINAL  SPINAL  NERVES.  509 

toes.  One  of  its  branches  sinks  down  with  the  anterior  tibial 
artery  to  the  sole  of  the  foot.  High  up  in  the  leg  it  gives  fila- 
ments to  the  knee-joint,  and,  in  its  course  downwards,  it  fur- 
nishes the  muscles  on  the  front  of  the  leg. 

The  Posterior  Tibial,  or  Popliteal  Nerve,  (Nervus  Popli- 
teuSj)  having  the  direction  mentioned,  is  placed  between  the 
skin  and  the  popliteal  vein.  It  gets  between  the  heads  of  the 
gastrocnemius  muscle,  and  perforates  the  origin  of  the  soleus; 
going  with  the  posterior  tibial  artery,  between  this  muscle  and 
the  flexor  longus  digitorum,  to  the  bottom  of  the  leg.  It  gives 
off  the  following  branches: — 

a.  The  External  Saphenus,  (Saphenus  Extermis,  or  Com- 
municans  Tibise?)  which  arises  above  the  knee-joint,  and,  de- 
scending between  the  skin  and  the  gastrocnemius,  turns  out- 
wardly, and  anastomoses  with  the  cutaneous  branch,  alluded  to, 
of  the  peroneal  nerve.     The  common  trunk,  thus  formed,  passes 
behind  the  external  ankle,  along  the  external  margin  of  the 
foot,  and  terminates  on  the  last  toes,  having  given  off  a  great 
number  of  cutaneous  branches. 

b.  Branches  to  the  heads  of  the  gastrocnemius,  soleus,  plan- 
taris,  and  popliteus. 

c.  Branches  to  the  flexor  longus  digitorum,  tibialis  posticus, 
and  to  the  flexor  longus  pollicis  pedis. 

d.  A  branch  through  the  interosseous  ligament,  above,  to  the 
tibialis  anticus. 

e.  At  the  inferior  part  of  the  leg  many  cutaneous  filaments, 
one  of  which  gets  to  the  sole  of  the  foot. 

The  Posterior  Tibial  Nerve,  having  givea  off  these  branches, 
divides,  in  the  hollow  of  the  os  calcis,  into  Internal  and  Exter- 
nal Plantar  Nerves. 

The  Internal  Plantar  (Plantaris  Internus)  proceeds  along- 
side of  the  tendon  of  the  flexor  longus  muscle  of  the  great  toe, 
and  the  flexor  longus  digitorum,  and  gives  filaments  to  the  con- 
tiguous muscles.     It  then  divides  in  such  a  way  as  to  furnish 
VOL.  II.— 65 


510  NERVOUS  SYSTEM. 

the  two  sides  of  the  three  first  toes  and  the  internal  side  of  the 
fourth. 

The  External  Plantar  (Plantaris  Externus)  proceeds  with 
the  artery  of  the  same  name  to  the  outer  edge  of  the  foot,  be- 
tween the  flexor  brevis  digitorum  and  the  flexor  accessorius. 
It  is  distributed  to  the  two  sides  of  the  little  toe,  and  to  the  ex- 
ternal side  of  the  fourth  toe.  One  branch  penetrates  to  the  in- 
terosseous  muscles  and  to  the  transversalis  pedis.  A  branch  of 
considerable  size  is  detached,  near  the  heel,  to  the  muscles  and 
integuments  connected  with  the  as  calcis* 


INDEX    TO    VOL.    II. 


Page 

Abdomen,  generally,                                      »  5 

General  'Situation  of  the  Viscera  of,     »  «            7 

Veins  of,  264 

Abdominal  Aorta,  Branches  of,              »                 .  .         222 

Absorbent  Glands  of  the  Abdomen,               .                 .  303 

Head  and  Neck,             .  .        292 

Lower  Extremity,  .                 ,  296 

Upper  Extremity,           .  .        294 

Thorax,  .                 .                 .  310 

Absorbents  of  the  Pelvis,       ....        297 

Head  and  Neck,                 .                .  290 
Upper  Extremities,  and  the  Contiguous 

Parts  of  the  Trunk  of  the  Body,  .        293 
Inferior  Extremities,  and  the  Contigu- 
ous Parts  of  the  Trunk  of  the  Body,  295 
Organs  of  Digestion,           .                .  299 
Parietes  of  the  Trunk,                .  .         307 
Viscera  of  the  Thorax,       .                .  305 
Absorbent  System,  Special  Anatomy  of,                .  .        290 
General  Anatomy  of,       .                »  281 
Accelerator  Urinae,                 .                 .                 .  .98 
Aorta,  and  the  Branches  from  its  Curvature,                 *  195 
Aqueous  Humour,                   «...         427 
Aqueducts  of  Ear,           ....  445 
Arachnoidea,          .....        345 
Areola,           .....  121 
Arcus  Sublimis,      .                .                .                 .  .219 
Arteries,         ....  195 
Texture  of,              .                .                .  .164 
Arteria  Basilaris,           .  381 
ad  Cutem  Abdominis,                .                 ,  238 
Alveolaris  Superior,           >                 .                 .  207 
Anastomotica,  (Arm,)                 .                „  ,        215 
Anastomotica,  (Thigh,)     .                 »                ,  241 
Articularis  Superior  Interna,  Thigh,         .  .         241 
Articularis  Superior  Externa,  "         .                .  242 
Articularis  M'edia,    »                «*                »  .        342 
Axillaris,               .                »                ,  212 


f>12  INDEX. 

Page 

Arteria  Articularis  Inferior  Externa,  Thigh,                  .  242 

Articularis  Inferior  Interna,      .                 .                 .  242 

Auricularis  Posterior,        .                  .                 .  204 

Brachialis,                 ....  212 

Buccalis,             .                 .                 .                 .  207 

Callosa,      .....  380 

Carotis  Primitiva,  .  .  .  197 
Carotis  Interna,  .  .  .  .198 

Carotis  Externa,                 .                 .                 .  199 

Cavernosa  Profunda  Penis,        .                .                .  235 

Coeliaca,    .                 .                 .                 .  223 

Cerebri  Posterior,      ....  382 

Cervicalis  Posterior,  .  .  .  210 
Choroidea,  .  .  .  .380 
Ciliaris,  ....  406, 420 

Circumflexa  Anterior  of  Axillaris,             .                 .  214 

Circumflexa  Posterior,       .                 .                .  214 

Circumflexa  Externa,                 .                 .                 .  239 

Circumflexa  Interna,         .                 .                 .  239 

Circumflexa  Ilii,        ....  237 

Colica  Sinistra  Superior,   .                 .                 .  227 

Colica  Sinistra  Media,         ,       .                 .                 .  227 

Colica  Sinistra  Inferior      .                 .                 .  227 

Communicans  Posterior  of  Brain,               .                 .  379 

Dentalis  Inferior,              .                 .                .  206 

Dorsalis  Carpi,          .                 .                 .                 .  217 

Dorsalis  Hallucis,               ...  245 

Dorsalis  Manus,        ....  219 

Epigastrica,        .  236 

Facialis,    .....  201 

Femoralis,         ....  237 

Frontalis,  .                 .                 .  408 

Gastrocnemea                    .                 .                 .  243 

Gastrica,   .....  223 

Gastrica  Dextra,                .                 .                 .  224 

'Gastrica  Sinistra,       ....  224 

Glutea,              ....  233 

Hsemorrhoidea  Inferior  Externa,                .                 .  235 

Haemorrhoidea  Media,       ...  232 

Haemorrhoidea  Superior  Interna,               .                .  227 

Hepatica,           ....  223 

Iliaca  Interna,           ....  230 

Iliaca  Externa,                   .                 .                 .  236 

llio-Lumbaris,           ....  230 

Innominata,       .                 .                .                .  197 

Intercostalis  Superior,               .                .                .  209 

Interossea  Anterior,           .                 .                 .  219 

Interossea  Posterior,                  .                 .                .  219 

Infra-Orbitalis,                   .                 .                 .  207 

Inferior  Cerebelli,      ....  381 

Ischiadica,         .  234 


INDEX.  513 

Page 

Arteria  Lachrymalis,  ....  406 

Lingualis,          ....  200 

Magna  Pollicis,          ...»  217 

Mammaria  Externa,  .  .  .  212 

Mammaria  Interna,    .  .  .  .210 

Maxillaris  Interna,  .  .  .  205 

Malleolaris  Externa,  .  .  244 

Malleolaris  Interna,  .  .  .  244 

Mesenterica  Inferior,  .  .  .  226 

Mesenterica  Superior,        .  .  .  225 

Metatarsea,  ....  245 

Meningea  Parva,  .  .  .  205 

Meningea  Magna       ....  205 

Muscularis  of  Orbit,  .  ,  .  407 

Nutritia,  Brachialis,  ....  215 

Nasalis,  ....  408 

Obturatoria,  .  .  .  .231 

Occipitalis,         ....  203 

CEthmoidea,  ....  407 

Palatina  Superior,  .  .  .  207 

Palrnaris  Profunda,   ....  217 

Palpebralis,        ....  408 

Peronea,    .  .  .  .  246 

Pedioea,  ....  245 

Perinea,     .....  235 

Pharyngea  Inferior,  .  .  .  202 

Pharyngea  Superior, ....  208 

Plantaris  Interna,  .  .  .  N  247 

Plantaris  Externa,     ....  247 

Poplitea,  ....  241 

Profunda  Femoris,    ....  238 

Profunda  Major  Humeri,  .  .  .  215 

Profunda  Minor,  "    .  .  .    '  .  215 

Pterygoidea,      ....  206 

Pudica  Interna,         ....  234 

Radialis,  ....  216 

Radialis  Indicia,    .  ...  217 

Recurrens  Radialis,  .  .  .  217 

Recurrens  Ulnaris,    ....  218 

Sacra  Media,    .  .  .  229 

Scapularis,  .  .  .  21 S 

Superior  Scapulae,  .  .  .  212 

Spheno-Palatina,       ....  208 

Superficialis  Volae,  .  .  .  217" 

Superior  Cerebelli,    .  .  .  .  332 

Splenica,  ....  224 

Subclaviana,  ....  208 

Tarsea,  ....  244 

Temporalis,  ,  .  .  .  204 

Thyroidea  Inferior,  .  .  .  209 

Thyroidea  Superior,  .  .  .  .199 


514  INDEX. 

Page 

Arteria  Thoracica  Longa,      ....  218 

Thoracica  Acromialis,         .                .                 ,  213 

Thoracica  Axillaris,    ....  213 

Transversalis  Faciei,           .                 »                »  204 

Temporalis  Media,      ....  205 

Temporalis  Profunda,         .                 »                 .  206 

Aorta,  Thoracic  Branches  of,     .                .                 .  220 

Thoracica  Superior,             .                 •.                .  213 

Tibialis  Anterior,        .                 .                 .  243 

Tibialis  Postica,  "...  246 

Tibialis  Recurrens,     ....  244 

Tympanica,         ...»  205 
Ulnaris,      .                .                .                .                .218 

Uterina,               ....  232 
Vertebralis,                  .                 .                 .                 209,  380 

Arteriae  Bronchiales,      ....  220 

(Esophageae,                ....  221 

Capsu  lares,         ....  227 

Emulgentes,                ....  227 

Gastricae  Breves,                 ...  225 

Gemellse,     .  243 

Intercostales  Inferiores  Aorticae,        .                .  221 

Iliacas  Primitivae,        ....  230 

Lumbares,           ....  228 

Mediastinales  Posteriores,          .                 .                 .  221 

Pancreaticae  Mediae  et  Sinistrae,        »                .  224 

Phrenicae,           .                 .                         .                .  222 

Profundae  Perforantes  Fempris,          .                *  240 

Pudendae  Externae,     .                                 .                .  238 

Sacrae  Laterales,                .                .                »  231 

Spermaticae,                 ....  228 

Vesicales,            ...»  232 

Arytenoid  Cartilages,             .  125 

Aryteno-Epiglottideus,                                                     .  129 
Arytenoideus  Obliquus,          .                 .                                 .129 

Trans  versus,              .                 .                 .  129 

Auditory  Nerve,     .....  447 
Axillary  Artery,  Branches  of,       .                                  .212 

Biliary  Ducts,        «...  61 

Bile,               .....  62 

Bladder,  .  .  .  .  .76 

Structure  of,                     ...  7? 
Blood,     .                 .                           .      .                 .                 .173 

Coagulating  Lymph  of,       .                .                .  177 

Red  Globules  of,                         .                .                .  178 

Serum  of,            .                 .                 .                 .  176 

Bones  of  Tympanum,              .                                 .                 .  437 

Brachial  Artery,  Branches  of,                        .                .  212 

Broad  Ligaments  of  the  Uterus,            .                ,  112 

Brain,             .....  335 


INDEX.  515 

Page 

Brain,  Veins  of,  .  .         382 

Carotids,  Branches  of,  .                .                .                .  198 

Capillaries,                              .  158 

Capsule  of  Glisson,        ....  13 

Caul,  Situation  of,                   ....  8 

Coecum,                                           •  37 

Cerebellum,            .....  351 

Cerebrum,      .....  354 

Chambers  of  Eye,  .                .                .                                 .  428 

Choroidea,      .....  414 

Chorda  Tjmpani,  .....  448 

Chylopoietic  Viscera,     ....  22 

Assistant,  .  .  .54 

Cilia,               .....  395 

Circulation  of  the  Foetus,  Peculiarities  of,             .                 .  271 
Peculiarities  of,  connected  with 

its  Nourishment,                .  276 

Circulatory  System,                ....  151 

General  Anatomy  of,      .                .  151 
Considerations  on  General  Anatomy 

of,                        .                .                .  151 

Special  Anatomy  of,       .                .  183 

Clitoris,  .  .  .  .  .105 

Coccygeus,  Muscle,       ....  100 

Cochlea,                  .....  442 

Colon,            .                .                .  .              .                .  38 

Commissura  Anterior,            ....  369 

Conjunctiva,  .....  396 

Corona  Glandis,     ....                 .  84 

Cornea,           .....  412 

Corpus,  Callosum,                   .                                 .                 .  360 

Cavernosurn,     ....  85 

Ciliare,      .....  414 

Dentatum,          .                .                 .                 .  353 

Fimbriatum,  .  .  .  .115 

Spongiosum,      ....  86 

Spongiosum  Vaginae,  .  .  .108 

Corpora  Striata,              ....  359 

Grura  Cerebri,  -      .                 .                .                .                 .  357 

Couper's  Glands,            ....  90 

Coronary  Arteries,  .  .  .  193,  197 

Veins,             .                .                .                .  194 

C remaster  Muscle,  .  .  .  .95 

Cricoid  Cartilage,           ....  124 

Crico-Arytenoideus  Posticus,                 .                 .                 .  128 

Lateralis,       .                .                 .  128 

Crico-Thyroideus,                   .                .                 .                .  128 

Dartos  Muscle,  :  .  .  .  91 

Ductus  Ejaculatorius,  .  .  .  .88 


516  INDEX. 

Page 

Ductus  Lactiferi,  .  .                .                .                         119 

Duodenum,    .                 .  .                 .                 .                   31 

Dura  Mater,           ,  336 

Sinuses  of,  ...                 339 

Ductus  Wirsungii,  .                .                .                .67 

Ear,               .                                 .                .                .  430 

Eminentise  Mammillares,       .... 

Olivares,      ... 
Epididymis,  ..... 

Epiglottis,      ...                 .                .                .  125 

Erector  Clitoridis,                   ....  106 

Penis,                 ....  98 

Eustachian  Valve,  .  .  .  .  .186 

Tube,          .... 

External  Iliac  Artery,  Branches  of,                       .                .  236 

Eye,               .....  394 

Eyeball,                 .               .               .               .  410 

Eyelids,         .               .               *              •               •  394 

Fallopian  Tubes,    .                .                .                .  .115 

Foetus,  Peculiarities  of,  arising  from  want  of  Respiration,  272 
Fornix,  .... 

Fossa  Navicularis,         ....  87 

Ovalis,         .                .                .                .  .186 

Fourchette,     .....  105 

Fourth  Ventricle,                    .                 .                 .  .370 

Frsenum  Penis,               .                .                .                »  84 

Frontal  Nerve,      ....  455 

Fundamental  Portion  of  Cerebellum,            .  354 

Ganglion  Cavernous,  ....        476 

Cervical,         ...  478 

Lumbar,  ....         486 

Lenticular,      ....  452 

Spheno-Palatine,     ....        392 

Sacral,  .  .  .  .  487 

Thoracic,  ....         482 

Gall  Bladder,  ....  59 

Glandulse  Odoriferae  Tysonii,  .  .  .84 

Pacchioni,     ....  344 

Palpebrarum,         ....        397 

Glandula  Pituitaria,       ....  358 

Pinealis,  ....        364 

Globus  Major,  ....  95 

Minor,        .  .  .  .  .95 

Glands  of  Brunner,        ....  26 

Peyer,    .  .  .  .  .31 

Head  and  Neck,  Veins  of,  .  .  249 

Heart,     .  .  .  .  .  .183 

Right  Auricle  of,  ...  185 

Right  Ventricle  of,      .  .  .  .178 


INDEX.        .  517 

Page 

Heart,  Left  Auricle  of,         .                .                .  .189 

Left  Ventricle  of,               .                ,                .  190 

Blood  Vessels  of,                        .                .  .        193 

Texture  of,                         .               .                .  191 

Hymen,                  .                .                .                .  .109 

Ileo-Colic  Valve,           .                .                •                .  37 

Ileum,     .                .                 .                 .                 .  .32 

Incus,            .                .                .                .                .  438 

Internal  Iliac  Artery,  Branches  of,                        .  .        230 

Inguinal  Glands,           ....  296 

Intestinal  Canal,    .                .                .                .  .27 

Intestine,  Small,            ....  28 

Large,    .                 ....  34 

Small,  Situation  of,        ...  8 

Large,  Situation  of,                ...  8 

Iris,                .                .                .                .                .  418 

Jejunum,                .                .                .                .  t.          32 

Kidneys,         .               .                .                .               .  70 

Situation  of,            .                .                .  .9 

Minute  Structure  of,       .                .               .  71 

Labia  Interna,        .                .                .                .  .        106 

Externa,              .                .                .                .  104 

Labyrinth,  .....        440 

Lachrymal  Apparatus,  ....  400 

Caruncle,            .                .             ,   .  .        402 

Ducts,     .    .                .                .                .   v  401 

Gland,                 .                .                .  .400 

Nerve,         .    •                            .                .  455 

Sac,     .                .                .                .  .403 

Larynx,          .                .                .                .                %  123 

Lateral  Ventricles,  ....        366 

Levator  Ani,                   .                ••                .                 ,  101 

Lens,      .                                 .                 .                 .  .425 

Ligamentum  Ciliare,      .                .                .                .  414 

Denticulatum,                   .                 .  .         329 

Palpebrale  Internum,              .  394 

Externum,      .               .  .        396 

Liver,             .                .                .                .                .  54 

Organization  of,          .                                ,  .          57 

Situation  of,        .                .                .  7 

Lower  Extremity,  Veins  of,  .                .                .  ,        262 

Lungs,           .                                .                .                .  141 

Texture  of,                  .                .                .  .142 

Lymphatic  Glands,                                                        i  287 

Mesocolon,             ....  34 

Malleus,         .                                ...  437 
Meatus  Externus,  .....        430 
VOL.  II.— 66 


518  INDEX. 

Mediastinum  Anterior, ....  147 

Posterior,           ....  147 

Superior,  ....  148 

Medulla  Oblongata,                ....  346 

Spinalis,  Nerves  of,  .  .        325, 488 

Membrana  Pupillaris,             ....  429 

Tympani,    .                 .                                  .  435 

Membranous  Labyrinth,        ....  443 

Mesentery,    .                 .                .                 .                .  33 

Mitral  Valve,         .  .  .  .  .190 

Mons  Veneris,                .                .                .                .  104 

Mucous  Glands,  and  Apparatus,  .  .  .88 

Membranes,  General  Anatomy  of,  .                .  48 

Musculus  Anterior  Auriculae,                .                .                .  434 

Antitragicus,                  .                 .                 .  433 

Attollens  Auriculae,               .                .                .  434 

Helicis,  Major  et  Minor,               .                .  433 

Laxator  Tympani,                  .                 .                .  439 

Levator,  Palpebrae  Su periods,       .                .  398 

Obliquus  Oculi  Superior,        .                 .                .  399 

Obliquus  Oculi  Inferior,                 .                 .  399 

Rectus  Oculi  Superior,          .                .                .  398 

Rectus  Oculi  Externus,                 .                 .  398 

Rectus  Oculi  Inferior,  .  .  .398 

Rectus  Oculi  Internus,  .                ,                .  399 

Retrahens  Auriculas,              .                 .                .  433 

Stapedius,       ....  439 

Tensor  Tarsi,         ....  404 

Tensor  Tympani,           .                .                .  439 

Tragicus,                 ....  433 

Transversus  Auriculae,                  .                .  433 

Mucous  Coat,  minute  Anatomy  of,        .                .-               .  40 

Nervous  System,  ....  315 
General  Anatomy  of,  .  .  .315 

Nasal  Nerve,                 ....  454 

Nerves  of  Encephalon,  ....  370 

Ear,  .  .  .  .  446 

Nervus  Abclomino  Cruralis,  .  .  .  503 

Abdominal  Spinal,  „  .  .  502 
Accessorius,  .  .  .  378,  468 

Auditorius,  ....  376 

Auricularis,  ....  464 

Cervical  es,  .  .  .  .  489 

Circumflexus,  ....  494 

Cruralis  Anterior,  .  .  .  505 

Cutaneus  Externus,  .  .  .  496 

Cutaneus  Internus,  .  .  .  495 

Cutaneus  Femuris  Externus,  .  .  504 

Cutaneus  Medius,  .  .  .  504 

Cutaneus  Femoris  Internus,  .  505 


INDEX.  519 


Nervus  Cutaneus  Anterior, 

Cutaneus  Femoris  Posterior, 

Descendens  Noni, 

Facialis, 

Glosso-Pharyngeus, 

Glutei,     . 

Hypoglossus,   . 

Infra  Maxillaris, 

Infra  Orbitalis, 

Ischiadicus, 

Laryngeus  Inferior, 

Laryngeus  Superior, 

Maxillaris  Superior, 

Medianus, 

Motor  Externus, 

Motor  Oculi, 

Nasalis  Internus, 

Naso-Palatinus, 

Obturatorius,     . 

Olfactorius, 

Opticus, 

Patheticus, 

Palatinus, 

Peroneus, 

Petrosus  Superficialis, 

Petrosus  Profundus,  . 

Pharyngeus  Superior, 

Phrenicus,      . 

Plantaris  Externus, 

Plantaris  Internus,     . 

Pneumogastricus, 

Portio  Dura, 

Portio  Mollis,     . 

Popliteus,  . 

Pudendalis  Superior, 

Pudendalis  Inferior, 

Pterygo-Palatinus, 

Radialis,     . 

Scapularis, 

Saphenus  Externus,   . 

Spermaticus  Externus, 

Splanchnicus, 

Spiralis, 

Subcostales, 

Suboccipitalis,  . 

Subscapularis, 

Sympatheticus,  . 


Sympathi 
Tris:emin 


Thoracici, 
Tibialis  Anterior, 
Trochlearis, 


520  INDEX. 

Page 

Nervus  Ulnaris,     .                .  .        498 

Vidianus,            ....  449, 458 

Neurilemma  of  Nerves,          ....        317 

Nose,             .                .                ...  383 

Blood  vessels  of,           .                .                .  .        393 

Nerves  of,                             .                                .  390 

Omenta,                 .               .                .               .  »          13 

Omentum  Colicum,        .  .14 

Omentum  Gastro  Splenicum,                 .                .  .15 

Majus,  or  Gastro  Colicum,            .                .  14 

Minus,  or  Hepatico  Gastricum,             .  .          13 

Ophthalmic  Nerve,.        .                                .                .  453 

Optic  Nerve,          .              ..                .                .  .371 

Orbit,  Arteries  of,                          .                .  406 

Nerves  of,    .                .                .                .  .        406 

Veins  of,              ....  409 

Orbiculare,  os,        .                .                .                .  .438 

Organs  of  Assimilation,                  .                .                .  4 

Generation,            .                .                .  .83 

Generation  in  the  Male,                 .                .  83 

Generation  in  the  Female,    .                .  .        104 

Respiration,  .                .                .                .  123 

OsTincae,             .                .               .               .  .111 

Ostium  Venosum*         ....  187,  190 

Ovaries,                 .               .               .                .  .116 

Pancreas,               .                .                .                .  .66 

Situation  of,     .                .                .                .  8 

Minute  Structure  of,               ..               .  .67 

Papilla  Mammae,           .               .                .                .  118 

Pelvic  Fascia,         .                .                .                .  .102 

Penis,             .                .                .                .                .  83 

Pericardium,          ...                r               .  .         184 

Perineal  Fascia,              ....  93 

Perineum,  Muscles  and  Fascia  of,                         .  .97 

Peritoneum,    .....  yio 

Pia  Mater,  .....         344 

Pigmentum  Nigrum,  of  Eye,          .                .                .  415 

Pituitary  Gland,    .....        358 

Membrane,     ....  386 

Pleurae,  .....         145 

Plexus  Brachialis,          ....  493 

Cardiacus,  .  480 

Choroides,           ....  368 

Cceliacus,    .....        484 

Coronarius,         ....  484 

Hepaticus,  ....        484 

Ischiadicus,        ....  506 

Lumbalis,    .                .                .                .  -       s  502 

Mesentericus  Inferior,        .                .                .  485 

Mesentericus  Superior,              .                .  .        485 


INDEX:  521 

Page 

Plexus  Diaphragmaticus,                        .                .  .         484 

Renalis,               ....  485 

Solaris,       .....        483 

Splenicus            ....  484 

Plica  Semilunaris,                  .                                .  .        402 

Pori  Biliarii,                   .                .                .                .  58 

Prepuce,                 .                .                 .                .  .84 

Primitive  Iliac  Artery,  Branches  of,             .                .  230 

Processus  Ciliaris,                  .                .                 .  .         415 

Prostate  Gland,              ....  89 

Protuberantia  Annularis,        ....         350 

Pulmonary  Artery,         .                .                .                .  189 

Recfum,                  .                .                .                .  .38 

Renal  Capsules,             ....  75 

Minute  Structure  of,  ,                .  .          75 

Situation  of,        ...  9 

Retina,   .                .                .                .                .  .421 

Round  Ligaments  of  the  Uterus,  .                .               .  113 

Sacculus  Ellipticus,  ....        444 

Sphericus,       .  444 

Sclerotica,               .                .                .                .  .411 

Scrotum,                        \  91 

Semicircular  Canals,             .                .                .  .441 

Seminal  Vesicles,           .                .                .                .  88 

Senses,  .                .                .                .                .  .383 

Serous  Membranes,  generally,      .               .                .  10 

General  Anatomy  of,             .  .18 

Septum  Lucidum,         ....  363 

Sinuses  of  Valsalva,               .                .                .  .191 

the  Vertebral  Column,                 .               .  257' 
Sinus  Cavernosus,                  ....        342 

Circularis,            ....  343 

Laterales,      .                .                 .                .  .340 

Longitudinalis,  Inferior,      .                .                .  341 

Longitudinalis,  Superior,              .                .  .        339 

Occipitalis,            ....  342 

Petrosi,         .                .                .                .  .341 

Quartus,                .                 .                .                 .  441 

Soemmering's  Foramen,         ....        422 

Spermatic  Chord,           ....  95 

Sphincter  Ani,        .                .                .                .  IQQ 

,  .     .  ._  ^ginae,  109 

fepinal  Marrow,      .  325 

Membranes  of,    .                .                .  331 

Nerves  of     .                .                .  .329 

Vessels  of,  334 

Spleen,  .                                •                •                .  .          62 

,  Situation  of,    •  .               .               .               .  g 

Intimate  Structure  of,              .               .  64 


522  INDEX. 

Page 

Stapes,           .                .                .  438 

Stomach,                 .                 .                 .                .  .22 

Situation  of,    .                                .  8 

Subclavian  Artery,  Branches  of,                            .  .        208 

Tarsi,             .....  396 

Taenia  Striata,        .                .                .                .  .360 

Tela  Choroidea,              .                 .  .              .                .  345 

Testicles,               .                                ...  90 

Minute  Structure  of,      .                .                .  94 

Thalami  Optici,      ...  .358 

Third  Ventricle,            ....  367 

Thyraus  Gland,      ...  .139 

Thyreo-Arytenoideus,  Muscle,      ...  128 

Epiglottideus,  ....        129 

Hyoideus,          ....  128 

Thyroid  Gland,     .                .                 .                .  .137 

Cartilage,          ....  124 

Thoracic  Aorta,  Descending  Branches  of,             .  .        220 

Ducts,             ....  310 

Trachea,                 .                .                .                •  .133 

Transversus  Perinei,  (Male,)        ...  99 

(Female,)              .                .  .109 

Triangular  Ligament  of  the  Urethra,             .                .  101 

Tubuli  Seminiferi,                 ;                .                .  .94 

Tuber  Cinereum,           ....  358 

Tubercula  Quadrigemina,      ....        365 

Tunica  Albuginea,         ....  93 

Hyaloidea,                  .                .                .  .424 

Vaginalis,            ....  92 

Tympanum,  .....        434 

Umbilical  Artery,          ....  277 

Vein,      .                .  276 

Upper  Extremity,  Nerves  of,         .                .                .  493 

Veins  of,          .                             .                 .  .258 

Ureter,           .                 .                 .                .                .  .  74 

Urethra,  (Male,)    .....  86 

(Female,)         .  .  .  .107 

Urinary  Organs,     .                .                .                .  .69 

Uterus,  and  its  Appendages,         .               .               .  110 

Vagina,    .                .                .                .                .  .107 

Valve  of  Vieussens,        .                .  353 

Vasa  Arteriarum,   .                .                .                 .  .168 

Efferentia,             ....  94 

Recta,            .                                                .  94 

Vorticosa,             .                .                .                .  417 

VasDeferens,        ...  96 

Vena  Azygos,                  .  256 

Axillaris,       .  261 

Basilica,               ....  260 


INDEX.  523 

Page 

Vena  Cava  Inferior,            ....  266 

Cava  Superior,  ....  255 

Cephalica,                  ...  259 

Choroidea,         ....  417 
Facialis,     .                .                .                .                .249 

Fernoralis,         ....  262 

'Hypogastrica,            ....  264 

Hemiazygos,     ....  256 

Iliaca  Externa,          ....  264 

Iliaca  Interna,  ....  264 

Iliaca  Primitiva,         ....  266 

Innominata,       ....  254 

Intercostalis  Superior,               .                .                .  256 

Jugularis  Externa,             .                 .                 .  252 

Jugularis  Interna,     ....  253 

Lingualis,          ....  250 

Mammaria  Interna,   ....  256 

Maxillaris  Interna,            .                .                .  252 

Mediana,  .....  260 

Meseraica  Inferior,            .                .                 .  269 

Meseraica  Superior, .                 .                .                .  270 

Occipitalis,        ....  251 
Ophthalmica,             .                .                 .                .409 

Palatina  Inferior,               .                .                .  250 
Pharjngea,                 .                .                 .                .251 

Poplitea,            ....  262 

Portarum,                   ....  269 

Ranina,              ....  250 
Sacra  Media,             .                .                .                .266 

Saphena  Minor  Externa,  .                .                .  262 

Saphena  Magna  Interna,           .                 .                .  263 

Splenica,            ....  269 

Subclavia,                  ....  261 

Submentalis,     ....  250 

Temporalis,               ....  252 

Temporalis  Superficial,  .                 .                 .  251 

Thjroidea  Inferior,    ....  255 

Thyroidea  Superior,          .                 .                 .  251 

Vertebralis,                ....  255 

Veins,  Texture  of,                        .                .                .  169 

Venae  Capsulares,                 ....  268 

Diploicae,            ,                .                .                .  251 

Emulgentes,               .  268 

Hepaticae,           .                                 .                .  268 

Lumbales,                  ....  267 

Phrenicae  Inferiores,           .                .                .  269 

Spehnaticae,               ....  267 

Ventricles  of  the  Brain,      .                .                .  366 
Verumontanum,   .                .                .                .                .89 

Vesical  Triangle,          .  '                               .                .  78 

Vestibulum  of  Vulva,           ....  107 


524  INDEX. 

Page 

Vestibulum,  Ear,  .  .  .  .         441 

Vitreous  Humour,        ....  423 

Vulva,.  .  ...         104 

Willis,  Circle  of,         .  .  .  .  382 

Winslow,  Fora-men  of,  .  .  .15 


THE  END. 


A    NEW    WORK. 


CAREY,   LEA   &  BLANCHARD,  Philadelphia, 

HAVE  JUST  PUBLISHED, 

POPULAR    MEDICINE; 

OR, 

FAMILY    ADVISER: 

CONSISTING  OF 

OUTLINES  OF  ANATOMY,  PHYSIOLOGY  AND  HYGIENE, 

WITH  SUCH  HINTS  ON  THE 

PRACTICE  OF  PHYSIC,  SURGERY, 

AND  THE 

DISEASES  OF  WOMEN  AND  CHILDREN, 


AS  MAY  PROVE    USEFUL    IN    FAMILIES  WHEN    REGULAR    PHYSICIANS    CANNOT  BE 

PROCURED  I 


BEING  A  COMPANION  AND  GUIDE  FOR  INTELLIGENT    PRINCIPALS  OF  MANUFACTORIES,    PLAN- 
TATIONS,   AND   BOARDING   SCHOOLS,    HEADS    OF    FAMILIES,    MASTERS   OF  VESSELS, 
MISSIONARIES,  OR  TRAVELLERS  ;  AND  A  USEFUL  SKETCH  FOR  YOUNG  MEN 
ABOUT  COMMENCING  THE  STUDY  OF  MEDICINE. 


BY  REYNELL  COATES,  M.  D., 

Fellow  of  the  College  of  Physicians  of  Philadelphia — Honorary  Member  of  the  Philadel- 
phia Medical  Society — Correspondent  of  the  Lyceum  of  Natural  History  of  New 
York — Member  of  the  Academy  of  Natural  Sciences  of  Philadelphia — Formerly  Resi- 
dent Surgeon  of  the  Pennsylvania  Hospital,  &c. — Assisted  by  several  Medical  Friends, 


IN  ONE  VOLUME,  OCTAVO. 


EXTRACTS  FROM  THE  PREFACE. 


"An  incalculable  advantage  which  results  from  the  extension  of  cor- 
rect medical  knowledge  beyond  the  limits  of  the  profession,  is  the  diffi- 
culty which  it  throws  in  the  way  of  the  ignorant  pretender,  by  enabling 
the  public  to  judge  more  correctly  of  medical  information.  For,  although 
the  writer  contemns  the  arrogance  of  those  who  have  ventured,  in  simi- 
lar works,  to  persuade  their  readers  that  all  opinions  differing  from  their 
own  are  the  offspring  of  ignorance  or  folly,  yet  he  believes  that  the 
principles  laid  down,  and  the  practical  directions  given,  in  the  following 
pages,  will  be  found  generally  in  accordance  with  received  doctrines. 
They  will  therefore  enable  the  patient,  or  his  friends,  so  to  direct  their 
questions  to  the  practitioner,  and  to  comprehend  the  replies,  as  to  dis- 
tinguish between  the  mere  empiric,  and  the  man  who  has  really  studied 
his  profession;  an  advantage  of  immense  value  to  both  parties,  in  situ 
ations  distant  from  large  cities. 

Among  the  strongest  proofs  of  the  propriety  of  the  present  undertak* 
ing,  are  the  constant  demand  for  a  popular  medical  guide  of  some  kind, 
and  the  circumstance  that  the  very  few  works  of  this  character  now 
extant,  which  can  be  considered  as  adapted  to  the  present  state  of  the 
science,  have  their  subject  matter  arranged  in  alphabetical  order: — an 
arrangement  which  precludes  the  possibility  of  preserving  the  recollec- 
tion of  the  mutual  relations  of  facts,  and  destroys  that  system  which  is 
best  calculated  to  aid  the  memory,  facilitate  reference,  and  impress  cor- 
rect principles. 

In  executing  his  task,  the  author  has  endeavoured  conscientiously  to 
inculcate  such  caution  as  is  calculated  to  secure  his  readers  against  a 
rash  dependence  upon  their  own  partially  enlightened  endeavours,  when 
other  and  more  efficient  assistance  is  at  hand,  while  he  has  exerted 
himself  to  communicate,  in  a  form  as  much  condensed  as  possible, 
whatever  information  he  considers  likely  to  aid  the  cause  of  humanity 
under  less  favourable  circumstances. 

These  explanations  are  due  to  the  practitioners  of  an  honourable  pro- 
fession. To  those  who  propose  to  commence  the  study  of  that  profes- 
sion, it  may  be  stated  that,  under  the  present  organization  of  our 
universities  and  medical  colleges,  the  pupil,  at  the  moment  of  entering 
upon  his  career,  is  overwhelmed  by  the  quantity  of  scientific  matter 
forced  upon  his  attention  by  the  number  and  variety  of  the  lectures  he 
is  called  upon  to  attend.  These  lectures  treat  of  a  variety  of  sciences, 
the  very  terminology  of  which  is  unknown  to  him;  and  much  of  the 
value  of  his  first  year  of  study  is  usually  lost  in  obtaining  a  few  general 
ideas,  laboriously  gleaned  from  a  great  mass  of  more  profound,  but,  to 
him,  unintelligible  learning.  Some  weeks  spent  in  perusing  and  reflect- 
ing upon  the  contents  of  the  first  three  chapters  of  the  present  work, 


will  communicate,  it  is  confidently  believed,  such  broad  views  and  im- 
pressions on  anatomical,  physiological,  and  hygienic  subjects,  as  will 
enable  him  to  listen  with  pleasure  and  advantage  to  the  first  course  of 
medical  instruction; — that  tedious,  and,  to  many,  almost  intolerable 
portion  of  the  labour  of  a  student. 

The  best  advice  that  can  be  given  to  an  individual  actually  suffering 
under  disease,  or  desirous  of  pursuing  such  a  course  of  diet,  exercise,  &c. 
as  is  likely  to  promote  his  health,  and  invigorate  and  preserve  the  force 
of  his  constitution,  is,  most  unquestionably,  to  recommend  a  consultation 
with  some  deservedly  eminent  physician.  But  the  directions  and  rea- 
sonings of  a  physician  are  better  understood  by  a  patient  who  has  him- 
self some  knowledge  of  the  first  principles  of  medicine.  This  knowledge 
is  also  a  protection  against  the  machinations  of  wonder-working  empi- 
rics; for  who,  that  has  the  slightest  idea  of  the  structure  of  the  most 
complicate  of  all  the  works  of  nature,  would  confide  the  management 
of  such  a  delicate  machine  to  the  hands  of  an  ignorant  pretender. 

It  is  not  always  possible  to  obtain  the  desired  assistance  in  due  time, 
and  in  many  situations  it  is  altogether  impracticable  to  obtain  it  at  alL 
There  is,  therefore,  no  intelligent  man  who  may  not  find  his  own  com- 
fort consulted,  and  his  sphere  of  usefulness  increased,  by  studying  the 
first  principles  of  physiology,  hygiene,  practical  medicine,  and  surgery. 

To  heads  of  families,  principals  of  large  manufactories,  seminaries, 
and  landed  estates,  missionaries  on  foreign  stations,  and  the  captains  of 
vessels,  such  knowledge  is  still  more  important. 

The  "  Family  Adviser"  being  designed  not  to  supersede  the  family 
physician,  but  merely  to  supply  his  place,  when  inaccessible,  it  will  be 
found  that  the  practical  part  of  the  work  dwells  chiefly  on  diseases  of 
an  acute  character,  and  that  when  chronic  complaints  are  mentioned, 
directions  for  the  management  of  the  earlier  stages  have  received  more 
attention  than  the  after  treatment.  Those  diseases  which  are  incurable 
in  their  nature,  or  which  defy  domestic  treatment  at  any  stage,  are  omit- 
ted, or  but  lightly  touched  upon  ;  and  when  such  remedies  or  operations 
as  are  employed  only  by  the  profession  become  the  subject  of  remark, 
they  are  introduced  merely  to  gratify  the  natural  curiosity  of  the  reader. 
When,  in  the  current  of  a  case,  the  requisite  treatment  becomes  danger- 
ous, or  demands  superior  skill,  the  subject  is  generally  fore-closed  by 
referring  the  reader  to  competent  medical  advisers. 

The  work  is  divided  into  two  parts ;  of  which  the  first  is  descriptive 
and  theoretical,  the  second  practical.  It  is  desirable  that  all  who  would 
qualify  themselves  for  rightly  comprehending  the  practical  part  should 
peruse,  previously  and  attentively,  the  first  four  chapters,  which  may  be 
regarded  as  introductory. 

An  Appendix  contains  a  list  of  many  of  the  simple  medicines  and 
compound  prescriptions  recommended  in  the  work,  with  the  mode  of 
preparing  the  latter.  It  is  remarked,  that  the  most  experienced  prac- 
titioners generally  employ  the  smallest  number  of  remedies,  as  the  most 
able  mechanic  often  uses  but  few  implements.  Instead,  then,  of  follow- 
ing the  example  of  his  predecessors,  by  perplexing  the  minds  of  his 
readers  with  a  history  of  a  great  multitude  of  medicines,  the  writer  has 
confined  his  attention  to  those  of^established  reputation,  and  named  in 
the  body  of  the  work." 


CONTENTS  OF  THE  VOLUME. 


PART  FIRST. 

OUTLINES    OF    ANATOMY,    PHYSIO- 
LOGY AND  HYGIENE. 


CHAPTER  I. 

PRELIMINARY    REMARKS     ON    THE 
ORGANIZATION  OF  ANIMALS. 

CHAPTER  II. 

STRUCTURE  OF  THE  HUMAN  BODY. 

Of  the  cellular  tissue. 
Of  fat,  or  adipose  tissue. 
Of  the  bones,  or  osseous  system. 
Of  the  skeleton. 

Of  the  muscles  or  muscular  system,  anato- 
my. 

Of  the  digestive  apparatus. 
Of  the  stomach. 
Of  the  duodenum. 
Of  the  liver. 
Of  the  pancreas. 
Of  the  small  intestine. 
Of  the  great  intestine. 
Of  the  circulation. 
Of  the  circulating  fluids. 
Of  the  route  of  circulation. 
Of  the  portal  vessels. 
Of  the  capillaries. 
Of  the  function  of  nutrition. 
Of  the  function  of  absorption. 
Of  respiration. 

Of  the  apparatus  of  respiration. 
Of  secretions. 
Of  the  urinary  apparatus. 
Of  the  urine. 

Of  the  skin  or  integument. 
Of  the  nerves. 
Of  the  brain. 
On  the  duplicature  of  certain  organs. 

CHAPTER  III. 

PHYSIOLOGICAL  REMARKS, 

Of  assimilation  and  nutrition. 
Of  the  reproduction  of  parts,  as  displayed 
in  the  healing  of  wounds. 


Of  symptomatic  fever. 

Of  irritation  and  hyper-nutrition,  inflamma- 
tion, physiological. 

Of  capillary  irritation. 

Of  nervous  irritation. 

Of  the  balance  of  vital  action  and  reaction. 

Of  vicarious  discharges  and  transformations 
of  tissues. 

CHAPTER  IV. 

REMARKS  ON  HYGIENE. 

Of  food. 

Of  clothing. 

Of  air  and  moisture. 

Of  exercise. 

Of  the  food  and  exercise  of  children. 

Errors  of  female  school  discipline. 

Of  matrimony. 


PART  SECOND. 

PRACTICAL  DIRECTIONS  FOR  THE 
TREATMENT  OF  MEDICAL  AND 
SURGICAL  DISEASES. 

CHAPTER  I. 

OF  SURGICAL  ACCIDENTS  AND 
DISEASES. 

SECT.  1. 

Of  wounds  and  contusions. 
Of  incised  wounds. 
Of  incised  wounds  of  the  scalp. 
Of  incised  wounds  of  the  neck  and  throat. 
Of  incised  wounds  of  the  chest. 
Of  incised  wounds  of  the  abdomen. 
Of  incised  wounds  of  the  joints. 
Of  lacerated  wounds. 
Of  contused  wounds. 
Of  contusions. 
Of  injuries  of  the  head. 

Concussion  of  the  brain, 
Fractures  of  the  skull. 
Of  contusions  in  the  cavity  of  the  spine. 
Of  fractures,  dislocations,  and  sprains  of  the 
spine. 


Of  concussions  of  the  spine, 

Of  contusions  of  the  chest. 

Of  contusions  of  the  abdomen. 

Of  contusions  of  the  pelvis  and  perineum. 

Fractures  of  the  pelvis. 

Of  contusions  or  sprains  in  the  joints. 

Of  punctured  wounds. 

SECT.  2. 

On  the  dilation  of  natural  passages,  and 
its  consequences. 

Dilation  of  the  anus. 

Of  dilated  or  varicose  veins. 

Of  varicocele. 

Of  piles,  or  hemorrhoids. 

Of  dilatations  of  the  heart  and  arteries. 

Of  aneurisms. 

Of  aneurismal  varix  and  varicose  aneurism. 

Of  mother-spots,  or  aneurism  from  anasto- 
mosis. 

Of  hernia,  or  rupture. 

r  SECT.  3. 

deformities  from  imperfect  nutrition  of 
the  osseous  and  muscular  systems. 
Of  curvatures  of  the  spine. 
Of  club  foot. 

SECT.  4. 
Of  fractures. 
Fractures  of  the  clavicle. 
Fractures  of  the  shoulder  blade. 
Fractures  about  the  shoulder  joint. 
Fractures  of  the  arm. 
Fractures  of  the  elbow  joint. 
Fractures  of  the  fore-arm. 
Fractures  of  the  lower  extremities. 
Fractures  of  the  thigh. 
Fractures  of  the  leg. 
Fractures  of  the  fingers  and  toes. 
Fractures  of  the  lower  jaw. 
Of  dislocations  in  general. 
Dislecations  of  the  arm  into  the  arm-pit. 
Dislocations  of  the  wrist. 
Dislocation  of  the  ankle,  with  fracture  of 
the  fibula. 

SECT.  5. 

On  inflammation  and  its  consequences. 
External  inflammations. 
Terminations  of  inflammation. 
Treatment  of  inflammation. 
Of  suppuration. 
Of  ulceration. 
Of  gangrene. 
Malignant  pustule. 
Gangrene  of  old  men. 
Dry  gangrene. 
Gangrene    from   excess    of  inflammation, 

from  internal  and  constitutional  causes. 
Gangrene  from  pressure. 
Gangrene  from  cold. 
Gangrene  from  mechanical  injuries. 
Terminations  of  inflammation  coupled  with 

collapse. 


Of  the  sty. 


Ulceration  of  the  eye-lashes. 
Foreign  substances  in  the  eye. 
Inflammation  of  the  eye. 
Ulceration  of  the  cornea. 
Films  on  the  eye. 
Foreign  bodies  in  the  ear. 
Ear-ache,  and  suppurations  of  the  ear. 
Ulcerations  of  the  mouth. 
Gum-biles. 

Suppurations  of  the  urinary  passages. 
Excoriations  about  the  mucous  orifices. 
Chafing. 
Of  abscesses. 
Run-round. 
Whitlow. 

Nails  growing  into  the  flesh. 
Biles. 

Furuncle  and  carbuncle. 
Canker,  or  gangrenous  sore  mouth  of  chil- 
dren. 

Burns  and  scalds. 
White  swelling. 
Hip-joint  disease. 

SECT.  6. 

Corns,  warts,  and  moles. 
Soft  corns. 
Warts. 
Moles. 

SECT.  7. 

Constitutional  diseases. 
Scrofula. 
Of  cancer. 
Venereal  diseases. 
Scurvy. 

CHAPTER  II. 

MEDICAL   PRACTICE    OR    TREAT- 
MENT OF  INTERNAL  DISEASES. 

SECT.  1. 
Fever. 

Intermittent  fever. 
Continued  fever. 
Billious  remittent  fever. 
Yellow  fever. 
Petechial  or  spotted  fever. 

.SECT.  2. 

Eruptive  diseases. 
Small-pox. 
Varioloid. 
Chicken-pox. 
Cow-pox. 
Measles. 
Scarlet  fever. 
Military  fever. 
Nettle-rash. 
Prickly  heat,  or  lichen. 
Shingles. 
Ring- worm. 
Itch. 

Rose-rash. 
Gum-rash. 
Pruriginous  rash. 


SECT.  3. 

Erysipelatous  affections. 
Poisoned  wounds. 

Erysipelas  phlegmonodes,  or   diffused  in- 
flammation of  the  cellular  tissue. 
Inflammation  of  the  veins  and  absorbents. 

SECT.  4. 

Diseases  of  the  respiratory  apparatus. 
Catarrh. 
Influenza. 
Pleurisy. 
Lung  fever. 
Consumption. 
Spitting-  of  blood. 
Pulmonary  hemorrhage. 
Asthma. 
Angina  pectoris. 

SECT.  5. 

Diseases  of  the  throat. 
Mumps. 
Quinsy. 
Croup. 

SECT.  6. 

Diseases  of  the  abdomen. 
Cholera  morbus. 
Spasmodic  or  malignant  cholera. 
Diarrhoea,  or  looseness. 
Dysentery. 
Colic. 

Painter's  colic. 
Liver  complaint. 
Inflammation  of  the  kidney. 
Jaundice. 

Passage  of  gall  stones. 
Worms. 

SECT.  7, 

Diseases  of  fibrous  tissue. 
Rheumatism. 
Gout. 

SECT.  8. 

Nervous  diseases. 

Chorea,  or  St.  Titus's  dance. 

Shaking  palsy. 

Convulsions. 

Epilepsy. 

Hysteria. 

Catalepsy,  or  trance, 

Apoplexy. 

Palsy. 

SBCT.  9. 

Prominent  symptoms  and  accident*. 
Dropsy. 
Heart-burn, 
Watev-brash, 
Flatulence. 
Costiveness. 

Indigestion;  or  dyspepsia* 
Vomiting. 
Hiccough. 
Crump. 


Bleeding  from  the  nose. 

Strangury. 

Diabetes. 

Gravel. 

Drowning. 

Death  from  suspension. 


CHAPTER  III. 


DISEASES  OF  MARRIED  WOMEN. 

Of  pregnancy,  and  the  position  and  connex- 
ions of  the  child  in  the  womb. 

Approach  of  labour. 

Of  labour. 

Uterine  hemorrhage. 

Of  puerperal  convulsions. 

Inversion  of  the  uterus. 

Inflammation  of  the  womb. 

Puerperal  fever. 

Swelled  leg,  milk  leg,  or  phlegmasia  do- 
lens. 

Puerperal  nervousness,  mania,  and  melan- 
choly. 

Of  palsy  of  the  bladder. 

Of  swelled  throat. 

Inflammation  and  abscess  of  the  mamma. 

Of  inflammation  of  the  nipple. 

CHAPTER  IV. 

ON  DISEASES  OF  CHILDREN. 

Tongue-tie. 

Swelled  breasts. 

Sore  navel. 

Of  the  yellow  skin  and  jaundice  of  infants. 

On  retention  and  suppression  of  urine. 

On  painful  urination. 

Incontinence  of  urine. 

Excessive  urination,  urinary  consumption, 

or  diabetes. 

Sore  mouth,  thrush,  aphthae. 
Colic. 

Costiveness. 
Vomiting. 
Erysipelas. 
Dentition. 
Worms. 
Convulsions. 
Dropsy  in  the  brain. 
Whooping-cough. 
Inflammation  of  the  tonsils,  quinsy. 
Cholera  infantum. 


CHAPTER  V. 

ON  DISEASES  OF  ADULT  FEMALES 

Appearance  of  the  menses. 
Chlorosis,  or  green  sickness. 
Suppression  of  the  menses. 
Obstructed  menstruation. 
Painful  menstruation. 


Excessive  menstruation,  or  flooding-. 
Final  cessation  of  the  menses. 
Leucorrhoea,  fluoralbus,  or  whites. 
Pluritis  vulvas. 

Falling-,  or  prolapsus  of  the  uterus. 
Retroversion,  or  falling-  of  the  womb  back- 
wards. 
Anti version  of  the  womb. 


Polypus  of  the  uterus. 
Cancer  of  the  uterus. 

Appendix. 
Formulary. 
List  of  drugs. 
List  of  apparatus. 
Index  to  Part  First. 
Index  to  Part  Second. 


From  amongst  many  commendatory  notices  of  the  work,  the  following  are 

selected : 

"This  work,  by  Dr.  Reynell  Coates,  is  by  far  the  best  of  its  class.  We  must  even 
add,  that  it  has  contributed  not  a  little  to  the  removal  of  our  fears  of  the  doubtful  if  not 
sinister  tendency  of  an  attempt  to  produce  a  system  of  Popular  or  Domestic  Medicine. 
Positive  good  will  result  to  them  who  shall  study  and  take  pains  to  acquire  a  knowledge 
of  the  facts  and  precepts  in  the  First  Part,  or  that  which  consists  mainly  of  an  '  Outline 
of  Anatomy*  and  'Remarks  on  Hygiene,'  in  the  work  before  us.  These  are  an  appro- 
priate and  a  necessary  introduction  to  the  Second  Part,  in  which  the  brief  indications  in 
the  treatment  of  diseases  and  accidents  by  the  aids  of  surgery  and  medicine,  are  set 
forth.  After  a  survey  of  his  labours  in  these  matters,  we  feel  inclined  to  join  in  opinion 
with  Dr.  Coates,  who,  in  his  preface,  expresses  his  belief  "that  the  principal  evils  which 
have  resulted  and  are  likely  to  result  hereafter  from  attempts  at  popular  medical  instruc- 
tion, are  attributable  rather  to  the  manner  in  which  the  subject  has  been  treated  than  to 
the  nature  of  the  subject  itself/  So  broad  is  the  contrast  between  both  the  matter  and 
the  manner  of  his  task,  and  the  systems  of  popular  medicine  hitherto  published,  that  the 
author  of  the  present  treatise  need  not  be  under  any  apprehensions  from  his  name  being 
placed  'in  juxtaposition  with  that  of  some  previous  authors,  whom  to  rival,  or  with 
whom  to  affiliate,  falls  not  within  the  compass  of  his  ambition.'  " 

"  Amongst  the  works  calculated  to  contribute  to  this  desirable  end,  of  enlightening 
people  generally  on  the  above  important  matters,  we  would  place  the  '  Family  Adviser* 
of  Dr.  Coates,  especially  that  portion  of  it  entitled  '  Outline  of  rfnatomy'  and  '  Remarks 
on  Hygiene*  The  first  is  a  clear  and  condensed  description,  with  illustrative  engravings, 
of  the  several  parts  of  which  the  living  body  is  composed.  The  second  abounds  with 
sound  and  practical  precepts  for  the  maintenance  of  these  parts  in  their  healthy  state 
separately  and  in  their  harmonious  relations  with  each  other." 

"  Under  the  successive  heads  of  Clothing  and  Cleanliness,  Air  and  Moisture,  Exer- 
cises, the  Food  and  Exercises  of  Children,  Errors  of  Female  School  Discipline,  and, 
finally,  of  Matrimony,  the  reader  will  find  a  large  amount  of  highly  instructive  and  avail- 
able matter.  It  is  pleasant  and  encouraging  to  see  a  man  of  talents  and  attainments,  and 
a  shrewd,  albeit  peculiar  observer,  engaged  in  enlightening  his  fellow  men  on  these  im- 
portant subjects.  That  they  will  thank  him,  and  prove  their  appreciation  of  his  services 
to  them  by  an  observance  of  his  precepts,  w^  can  readily  believe,  as  we  sincerely  hope." 

ticket  Medical  Library. 

«« This  is  a  very  neatly  executed  work,  from  the  prolific  press  of  Carey,  Lea  &  Blanch- 
ard.  The  title  of  the  volume,  perhaps,  would  not  recommend  it  to  the  profession,  who 
have  had  just  occasion  to  be  disgusted  with  treatises  on  domestic  medicine,  medical  ad- 
visers, 8cc.  -,  but  emanating  from  so  high  a  source,  we  shall  be  much  disappointed  if  this 
volume  does  not  ensure  for  itself  a  careful  perusal  from  the  scientific  practitioner,  for 
which,  we  will  predict,  he  will  be  amply  repaid.  So  far  as  we  can  allow  ourselves  to 
approve  of  epitomes  on  medical  subjects,  we  must  distinguish  this  volume  as  the  deposi- 
tory of  a  large  fund  of  anatomical,  physiological  and  practical  truth.  But  to  families, 
travellers,  members  of  missionary  stations,  and  all  who  may  be  unable  to  procure  the 
services  of  a  regular  practitidner,  it  is  a  valuable  compendium,  and  for  such  the  work 
was  expressly  designed. 

"But  the  author,  apart  from  this,  had  another  object  to  accomplish,  which  the  en- 
lightened practitioner  will  deem  desirable,  viz.,  the  extension  of  correct  medical  know- 
ledge beyond  the  limits  of  the  medical  profession.  We  have  long  considered  this  a 
desideratum.  Such  a  purpose  gained,  will  do  more  towards  pulling  down  the  strong- 
holds of  quackery  and  empiricism,  in  their  thousand  Protean  forms,  than  the  fast-multi- 


plying1  prosecution  and  accumulated  verdicts  of  homicide  can  ever  accomplish.  A  volume 
like  this,  carefully  read,  will  enable  the  public  to  distinguish  easily  between  the  pre- 
tender and  the  man  who  has  faithfully  studied  his  art.  When  public  opinion  is  enlight- 
ened, we  may  invoke  its  resistless  arm  to  our  aid  in  the  cause  of  science  and  humanity. 
Give  to  any  patient  the  slightest  knowledge  of  the  structure  of  his  system,  or  the  faintest 
idea  of  the  principles  of  the  medical  art,  and  he  will  hesitate  before  he  entrusts  the  re- 
pairing of  such  delicate  machinery  to  the  hands  of  the  marvellous-loving  and  wonder- 
working- quack. 

"  We  have  time  only  for  a  cursory  notice  of  the  plan  of  the  work.  It  is  divided  into 
two  general  parts,  descriptive  or  theoretical,  and  practical.  The  first  embraces  a  parti- 
cular notice  of  human  general  anatomy,  enlivened  with  many  physiological  observations 
— a  view  of  the  principal  animal  functions,  and  their  aberration  from  healthy  action — and 
a  very  valuable  chapter  on  hygiene.  Part  second  treats  of  the  symptoms  of  diseases  and 
the  most  approved  methods  of  treatment. 

"  WTe  cannot  close  this  notice,  without  special  commendation  of  many  portions  from 
which  we  shall  be  glad  to  make  extracts.  That  portion  of  the  chapter  on  hygiene,  treat- 
ing of  clothing,  exercise,  and  errors  in  female  education,  should  be  faithfully  studied  by 
every  conductor  of  seminaries  for  the  education  of  females  throughout  the  Common- 
wealth. The  article  on  spinal  curvatures  we  commend  to  them  as  replete  with  valuable 
hints  on  physical  education.  The  clearness  and  simplicity  of  the  style  of  the  work  will 
be  admired  by  the  profession,  as  well  as  the  general  reader  for  whom  it  is  adapted." 

Boston  Medical  Journal. 

"It  is  with  great  satisfaction  that  we  announce  this  truly  valuable  compilation,  as  the 
most  complete  and  interesting  treatise  on  popular  medicine  ever  presented  to  the  pub- 
lic. Simple  and  unambitious  in  its  language,  free  from  unintelligible  technicalities  and 
embracing  the  most  important  facts  in  Anatomy,  Physiology,  Hygiene,  or  the  art  of  pre- 
serving health,  and  the  treatment  of  those  affections  which  require  immediate  attention, 
or  are  of  an  acute  character — this  should  be  in  the  hands  of  every  one,  more  particu- 
larly those  who,  by  their  situation  are  prevented  from  resorting  to  the  advice  of  a  physi- 
cian, nor  would  the  careful  perusal  of  its  pages  fail  to  profit  the  inhabitants  of  our  cities. 
By  giving  them  a  more  accurate  knowledge  of  the  structure  of  the  human  frame  and  of 
the  laws  that  govern  its  various  functions,  whose  perfect  integrity  is  absolutely  essential 
to  health,  and  even  to  existence;  the  various  systems  of  medical  charlatanry  daily  imagin- 
ed to  take  advantage  of  the  credulity  and  ignorance  of  mankind,  would  be  rendered  far 
less  prejudicial  to  the  community  than  they  now  are.  We  would  particularly  direct 
attention  to  the  chapter  on  Hygiene,  a  science  in  itself  of  the  utmost  importance,  and 
ably  treated  in  the  small  space  allowed  to  it  in  this  volume." — New  York  American. 

"  Let  it  have  a  fair  examination,  say  we — and  our  word  for  it,  this  most  useful,  and 
we  had  almost  added,  national  publication,  will  progress  triumphantly  through  many 
editions.  Dr.  Coates  has  rightly  appreciated  the  mind  of  the  Americans,  and  has  pro- 
duced the  only  really  valuable  and  complete  work  as  a  «  Family  Medicine'  that  we  have 
yet  seen;  while  he  has  shown  the  comprehensiveness  of  his  own  mind,  in  devoting  the 
first  part  of  the  volume  to  giving  plain  and  philosophical  outlines  of  Anatomy,  Physiolo- 
gy and  Hygiene.  A  second  part  developes  many  of  the  mysteries  of  surgery,  affording 
practical  directions  for  the  treatment  of  Medical  and  Surgical  Diseases.  In  the  earlier 
portion  of  *  Popular  Medicine,' therefore,  the  intelligent  reader  becomes  familiar  with 
the  entire  structure  of  the  human  body.  He  is  then  led  into  the  doctrines  of  assimila- 
tion, nutrition,  nervous  and  other  irritation,  inflammation,  vital  action  and  re-action,  &c. ; 
while  the  chapter  on  Hygiene,  gives  him  valuable  information  with  regard  to  food,  cloth- 
ing, air,  exercise,  matrimony,  &c.  Thus,  like  a  sound  and  skilful  professor  of  languages 
— the  learned  Doctor  begins  with  endeavouring  to  ground  his  readers  in  the  grammar  of 
the  healing  art,  if  we  may  be  allowed  such  an  application  of  the  word;  well  knowing  the 
danger  of  total  ignorance  in  those  who  administer  medicine  in  any  form  or  under  any 
circumstances. 

"  To  our  thinking,  and  we  have  carefully  examined  its  pages— there  should  be  a  copy 
of  it  in  every  American  family  and  in  every  American  ship;  and  in  stating  our  belief 
that  before  many  years  shall  have  passed  away,  such  will  be  almost  the  result — we  are 
of  opinion  that  we  only  speak  the  words  of  a  true  prophecy."— Saturday  Chronicle. 


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